Helping out: short tasks

Would you like to help out at a PR, differently from reviewing? Here are some ideas:

take a look at PRs with just some mathlib-infrastructure-related CI failure: unless it's an infrastructure PR, these are spurious/not the PRs fault. If the failure is spurious, commenting to this effect can be helpful.
take a look at PRs labelled help-wanted or please-adopt
If the author hasn't noticed, you can ask in a PR which just has a merge conflict, but would be reviewable otherwise. (Remember, that most contributors to mathlib are volunteers, contribute in their free time and often have other commitments — and that real-life events can happen!)
check if any 'stale' PR by a new contributor benefits from support, such as help with failing CI or providing feedback on the code
check if any 'stale' delegated PR benefits from support, such as by fixing merge conflicts (but be sure to ask first; the PR author might simply be very busy)

This dashboard was last updated on: June 02, 2026 at 14:55 UTC

PRs with just failing CI, but only often-spurious jobs

Number	Author	Title	Description	Labels	+/-	Modified files (first 100)	📝	💬	All users who commented or reviewed	Assignee(s)	Updated	Last status change	total time in review
28803	astrainfinita author:astrainfinita	refactor: unbundle algebra from `ENormed*`	Further speed up the search in the algebraic typeclass hierarchy by avoiding searching for `TopologicalSpace`. This PR continues the work from #23961. - Change `ESeminormed(Add)Monoid` and `ENormed(Add)Monoid` so they no longer carry algebraic data. - Deprecate `ESeminormed(Add)CommMonoid` and `ENormed(Add)CommMonoid` in favor of `ESeminormed(Add)Monoid` and `ENormed(Add)Monoid` with a commutative algebraic typeclass. \|Old\|New\| \|---\|---\| \| `[ESeminormed(Add)(Comm)Monoid E]` \| `[(Add)(Comm)Monoid E] [ESeminormed(Add)Monoid E]` \| \| `[ENormed(Add)(Comm)Monoid]` \| `[(Add)(Comm)Monoid E] [ENormed(Add)Monoid]` \| See [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/144837-PR-reviews/topic/.2328803.20refactor.3A.20unbundle.20algebra.20from.20.60ENormed*.60/with/536024350) ------------ - [x] depends on: #28813	t-algebra merge-conflict slow-typeclass-synthesis awaiting-zulip t-analysis label:t-algebra$	80/63	Mathlib/Analysis/CStarAlgebra/CStarMatrix.lean,Mathlib/Analysis/Normed/Group/Basic.lean,Mathlib/Analysis/Normed/Group/Continuity.lean,Mathlib/Analysis/Normed/Group/InfiniteSum.lean,Mathlib/Analysis/NormedSpace/IndicatorFunction.lean,Mathlib/MeasureTheory/Function/L1Space/AEEqFun.lean,Mathlib/MeasureTheory/Function/L1Space/HasFiniteIntegral.lean,Mathlib/MeasureTheory/Function/L1Space/Integrable.lean,Mathlib/MeasureTheory/Function/LocallyIntegrable.lean,Mathlib/MeasureTheory/Function/LpSeminorm/Basic.lean,Mathlib/MeasureTheory/Function/LpSeminorm/CompareExp.lean,Mathlib/MeasureTheory/Function/LpSeminorm/TriangleInequality.lean,Mathlib/MeasureTheory/Integral/IntegrableOn.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/Basic.lean	14	28	['astrainfinita', 'bryangingechen', 'github-actions', 'grunweg', 'kbuzzard', 'leanprover-bot', 'leanprover-community-mathlib4-bot', 'mathlib-bors', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'sgouezel']	grunweg assignee:grunweg	272-54042 8 months ago	281-5196 281 days ago	0-19244 5 hours
30451	kckennylau author:kckennylau	feat(HomogeneousIdeal): generalize to homogeneous submodule	Continuation of #30437 with permission from @jjaassoonn, which is a continuation of #9820 . The definitions, constructions and theorems in `HomogeneousIdeal.lean` are generalized to homogeneous submodules. Let `R` be a graded ring and `M` be a graded `R`-module. Say an `R`-submodule `N` of `M` is homogeneous if for every `x` in `N`, each projection of `x` to `M_i` is in `N`. None of this file's results depends on the grading on `R`, but we include the grading on `R` for technical reasons. We define the "homogeneous core" of a not necessarily homogeneous submodule N to be the biggest homogeneous submodule contained within N, and the "homogeneous hull" to be the smallest homogeneous submodule that contains N. All definitions/constructions/theorems are then copied for ideals/homogeneous ideals. The motivation of this generalization is graded quotient module. (#18716) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory awaiting-author merge-conflict	581/185	Mathlib/Algebra/BigOperators/Finsupp/Basic.lean,Mathlib/Algebra/DirectSum/Basic.lean,Mathlib/Algebra/DirectSum/Decomposition.lean,Mathlib/Algebra/DirectSum/Finsupp.lean,Mathlib/Algebra/Module/GradedModule.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Basic.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Scheme.lean,Mathlib/RingTheory/GradedAlgebra/Homogeneous/Ideal.lean,Mathlib/RingTheory/GradedAlgebra/Homogeneous/Submodule.lean,Mathlib/RingTheory/GradedAlgebra/Radical.lean	10	23	['github-actions', 'mariainesdff', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot']	mariainesdff assignee:mariainesdff	83-150 2 months ago	83-150 82 days ago	22-61022 22 days
33466	Shreyas4991 author:Shreyas4991	refactor(Combinatorics/Digraph): add vertex sets	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics merge-conflict please-adopt	382/55	Mathlib/Combinatorics/Digraph/Basic.lean,Mathlib/Combinatorics/Digraph/Orientation.lean	2	83	['IvanRenison', 'Shreyas4991', 'SnirBroshi', 'YaelDillies', 'copilot-pull-request-reviewer', 'github-actions', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot', 'vihdzp', 'vlad902']	awainverse assignee:awainverse	81-31859 2 months ago	81-31859 81 days ago	27-54021 27 days
37556	edwin1729 author:edwin1729	feat(Topology/Order): Locale.localePointOfSpacePoint if we have a Scott Topology from an Algebraic DCPO	(3/4) in a series of PRs proving that "Scott Topologies over Algebraic DCPOs are Sober" We prove here that the unit of the adjunction from `TopCat` to `Locale` defined in `Topology/Order/Category/FrameAdjunction.lean` is a surjective mapping, under the following condition: The underlying TopologicalSpace must be a Scott Topology generated with an underlying Algebraic DCPO structure. - [ ] depends on: #37445 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor blocked-by-other-PR merge-conflict	393/1	Mathlib.lean,Mathlib/Topology/Order/ScottTopology.lean,Mathlib/Topology/Order/ScottTopologyDCPO.lean,docs/references.bib	4	5	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	35-55247 1 month ago	60-79747 60 days ago	0-562 9 minutes
36896	PieterCuijpers author:PieterCuijpers	feat (Algebra/Order/Quantale): isMulLeftsided, isMulRightsided, isMulTwosided and strict versions	* Adding definitions of quantale elements being leftsided, rightsided, and twosided, and strict versions Should we include these definitions in the main Algebra/Order/Quantale.lean file, or start a separate file for them? I have a few basic theorems I would like to include on these notions, but invite suggestions. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author label:t-algebra$	81/1	Mathlib/Algebra/Order/Quantale.lean	1	5	['NoahW314', 'PieterCuijpers', 'chrisflav', 'github-actions']	mariainesdff assignee:mariainesdff	28-5340 28 days ago	34-83995 34 days ago	39-15412 39 days
39108	idontgetoutmuch author:idontgetoutmuch	feat(Geometry/Manifold/GroupLieAlgebra): Add mfderiv_mul_left_mul and left-translate for integral curves	Add the following: `mfderiv_mul_left_mul`: the derivative of left-multiplication satisfies a chain rule: $$d(L_{g \cdot h})_x = d(L_g)_{h \cdot x} \circ d(L_h)_x$$ `mulInvariantVectorField_mul`: the vector field at the translated point is the push forward of the vector field: $$V(g \cdot h) = d(L_g)_h(V(h))$$ `IsMIntegralCurve.left_translate`: using these, if $\gamma$ is an integral curve of $V$, then so is $t \mapsto g \bullet \gamma(t)$ for any $g \in G$, since: $$\frac{d}{dt}(g \bullet \gamma(t)) = d(L_g)_{\gamma(t)}\left(\frac{d\gamma}{dt}(t)\right) = d(L_g)_{\gamma(t)}(V(\gamma(t))) = V(g \bullet \gamma(t))$$ I argue () all the time with LLMs so this PR will certainly have had some input from them. Is that enough of a disclosure? () Like Lewis Carroll: In my youth said the sage I took to the law and argued each case with wife And the muscular strength that it gave to my jaw has lasted the rest of my life	t-differential-geometry new-contributor awaiting-author LLM-generated	73/0	Mathlib/Geometry/Manifold/GroupLieAlgebra.lean	1	8	['github-actions', 'grunweg']	nobody	23-75462 23 days ago	23-75527 23 days ago	0-37210 10 hours
32828	Hagb author:Hagb	feat(Algebra/Order/Group/Defs): add `IsOrderedAddMonoid.toIsOrderedCancelAddMonoid'`	It is similar to `IsOrderedAddMonoid.toIsOrderedCancelAddMonoid`, while with different hypotheses. The conclusion `IsOrderedCancelMonoid α` on `IsOrderedAddMonoid.toIsOrderedCancelAddMonoid` still holds when the hypothesis `CommGroup α` is weakened to `CancelCommMonoid α` while `PartialOrder α` is strengthened to `LinearOrder α`. --- [`IsOrderedAddMonoid.toIsOrderedCancelAddMonoid`](https://leanprover-community.github.io/mathlib4_docs/find/?pattern=IsOrderedAddMonoid.toIsOrderedCancelAddMonoid#doc) and `IsOrderedAddMonoid.toIsOrderedCancelAddMonoid'`: https://github.com/leanprover-community/mathlib4/blob/97f78b1a4311fed1844b94f1c069219a48a098e1/Mathlib/Algebra/Order/Group/Defs.lean#L52-L62 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-zulip t-algebra awaiting-author label:t-algebra$	4/0	Mathlib/Algebra/Order/Group/Defs.lean	1	15	['Garmelon', 'Hagb', 'Vierkantor', 'artie2000', 'dagurtomas', 'github-actions', 'leanprover-radar']	eric-wieser assignee:eric-wieser	16-47104 16 days ago	130-83527 130 days ago	40-36049 40 days
39820	samuelchassot author:samuelchassot	Add proof of the existence of an Eulerian walk if all vertices have even degree or if exactly vertices have odd degree	As per the TODO open in `Trails.lean`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	671/3	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Eulerian.lean,Mathlib/Combinatorics/SimpleGraph/Trails.lean	3	8	['SnirBroshi', 'copilot-pull-request-reviewer', 'github-actions']	nobody	8-7105 8 days ago	8-7498 8 days ago	8-7248 8 days
39877	kim-em author:kim-em	feat(ci): cross-reference tag review via post-build dump + workflow_run shim	This PR adds the cross-reference tag review pipeline on the mathlib4 side. Three new steps in `post_steps` of [build_template.yml](.github/workflows/build_template.yml) run `scripts/dump_crossref_tags.lean`, upload its TSV unconditionally as a plain `crossref-tags-baseline` artifact (30-day retention), and on PR builds also emit a privileged `crossref-tags-bridge` via [`privilege-escalation-bridge`](https://github.com/leanprover-community/privilege-escalation-bridge). A new [crossref_review.yml](.github/workflows/crossref_review.yml) workflow_run listener consumes the bridge, caches and pre-builds `crossref-render` from a pinned [external-tags](https://github.com/leanprover-community/external-tags) ref, and invokes the orchestrator in [mathlib-ci #44](https://github.com/leanprover-community/mathlib-ci/pull/44). Trust model: the privileged job runs only code from `mathlib-ci@` (which in turn only runs `external-tags@`). The TSV is parsed as untrusted data; user-controllable fields are escaped before going into the bot comment. - [ ] depends on: #39876 🤖 Prepared with [Claude Code](https://claude.com/claude-code)	CI blocked-by-other-PR	265/0	.github/workflows/build_template.yml,.github/workflows/crossref_review.yml,scripts/README.md,scripts/dump_crossref_tags.lean	4	2	['github-actions', 'mathlib-dependent-issues']	nobody	6-1845 6 days ago	unknown	unknown
38169	tb65536 author:tb65536	chore(GroupTheory/Finiteness): make `Subgroup.FG` a class	This PR refactors `Subgroup.FG` to be a class to match `Group.FG`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra t-group-theory label:t-algebra$	37/20	Mathlib/GroupTheory/Commutator/Finite.lean,Mathlib/GroupTheory/Finiteness.lean,Mathlib/GroupTheory/Rank.lean,Mathlib/GroupTheory/Schreier.lean	4	10	['JovanGerb', 'github-actions', 'mathlib-bors', 'riccardobrasca', 'tb65536']	mattrobball assignee:mattrobball	4-48566 4 days ago	32-1247 32 days ago	45-75554 45 days
39347	Sfgangloff author:Sfgangloff	feat(SymbolicDynamics): refactor of Pattern and shift-invariance of shape languages for subshifts	## Summary This PR refactors Pattern.mulShift in Mathlib/Dynamics/SymbolicDynamics/Basic.lean and uses the cleaner definition to prove shift-invariance of the language of a subshift on a finite shape. ## Changes Pattern.mulShift now returns a Pattern instead of a configuration (more natural). - Old type: Pattern.mulShift : Pattern A G → G → (G → A) - New type: Pattern.mulShift : Pattern A G → G → Pattern A G - The result carries its support (p.support.image (v * ·)) and the default-outside-support proof, so callers don't have to re-derive them. The [IsLeftCancelMul G] hypothesis is moved to the lemmas that actually use it. - The definition Pattern.mulShift itself no longer needs left-cancellation (it only chooses a preimage noncomputably). - The hypothesis is now stated on mulShift_config_apply_mul_left_of_mem and mulOccursInAt_eq_cylinder directly, instead of being a section-level variable. Renames following the type change. - mulShift_apply_mul_left_of_mem → mulShift_config_apply_mul_left_of_mem (because we now write (p.mulShift v).config instead of p.mulShift v). New @[simp] and @[ext] lemmas for Pattern. - Pattern.ext: two patterns are equal iff their supports agree and their configurations agree on the support. - Pattern.mulShift_support: the support of p.mulShift v is p.support.image (v * ·). - Pattern.fromConfig_support: the support of fromConfig x U is U. - Pattern.fromConfig_config_of_mem: on its support, fromConfig x U agrees with x. New lemma Pattern.fromConfig_mulShift. For a left inverse g' * g = 1, shifting the pattern fromConfig x U by g equals fromConfig (mulShift g' x) (U.image (g * ·)). New theorem MulSubshift.languageOn_image_mulShift. For a subshift Y and elements g, g' with g * g' = 1 and g' * g = 1: (fun p => p.mulShift g) '' Y.languageOn U = Y.languageOn (U.image (g * ·)) i.e. the language on the translated shape is exactly the image of the language on U under the pattern-shift map. This gives a bijection between Y.languageOn U and Y.languageOn (U.image (g * ·)), with inverse p ↦ p.mulShift g'. Stated for left-cancellative monoids with an invertible element. Updated docstrings for Pattern.mulShift and the renamed lemma to reflect the bundled-Pattern return type and clarify which results need [IsLeftCancelMul G].	t-dynamics new-contributor	142/48	Mathlib/Dynamics/SymbolicDynamics/Basic.lean	1	3	['github-actions']	sgouezel assignee:sgouezel	4-48559 4 days ago	19-43125 19 days ago	19-42875 19 days
40020	kbuzzard author:kbuzzard	wip	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra label:t-algebra$	38/27	Mathlib/Algebra/Group/Pi/Basic.lean	1	4	['github-actions', 'kbuzzard', 'leanprover-radar']	nobody	3-80661 3 days ago	3-78415 3 days ago	3-78165 3 days
39388	marcelolynch author:marcelolynch	chore: remove @[expose] from def-free public sections	Strip `@[expose]` from `public section` headers in 100 modules where no declaration needs its body visible downstream. A new sweep in the style of #38480 Found using the linter-in-progress: #39387 Relevant Zulip thread: https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Removing.20unnecessary.20.60.40.5Bexpose.5D.60/with/595180230	merge-conflict	100/100	Mathlib/Algebra/Category/Ring/Small.lean,Mathlib/Algebra/Field/Basic.lean,Mathlib/Algebra/Field/MinimalAxioms.lean,Mathlib/Algebra/Field/Opposite.lean,Mathlib/Algebra/Field/Rat.lean,Mathlib/Algebra/Field/ULift.lean,Mathlib/Algebra/Field/ZMod.lean,Mathlib/Algebra/Group/Action/Option.lean,Mathlib/Algebra/Group/Action/Sigma.lean,Mathlib/Algebra/Group/Action/Sum.lean,Mathlib/Algebra/Group/Action/Units.lean,Mathlib/Algebra/Group/Subgroup/Actions.lean,Mathlib/Algebra/Group/Submonoid/MulAction.lean,Mathlib/Algebra/Module/Projective.lean,Mathlib/Algebra/Module/Submodule/Basic.lean,Mathlib/Algebra/NonAssoc/LieAdmissible/Defs.lean,Mathlib/Algebra/Notation/Prod.lean,Mathlib/Algebra/Order/Floor/Div.lean,Mathlib/Algebra/Order/Group/Action/End.lean,Mathlib/Algebra/Order/Group/End.lean,Mathlib/Algebra/Order/Group/PosPart.lean,Mathlib/Algebra/Order/Kleene.lean,Mathlib/Algebra/Order/Nonneg/Lattice.lean,Mathlib/Algebra/Order/Pi.lean,Mathlib/Algebra/Order/Ring/Unbundled/Rat.lean,Mathlib/Algebra/Ring/Commute.lean,Mathlib/AlgebraicTopology/ModelCategory/Over.lean,Mathlib/Analysis/InnerProductSpace/Coalgebra.lean,Mathlib/Analysis/Normed/Algebra/TrivSqZeroExt.lean,Mathlib/Analysis/Normed/Group/Constructions.lean,Mathlib/Analysis/Normed/Module/MStructure.lean,Mathlib/Analysis/Normed/Operator/Compact/FiniteDimension.lean,Mathlib/Analysis/ODE/DiscreteGronwall.lean,Mathlib/CategoryTheory/Localization/DerivabilityStructure/OfLocalizedEquivalences.lean,Mathlib/CategoryTheory/MarkovCategory/Positive.lean,Mathlib/CategoryTheory/Monoidal/Cartesian/Normal.lean,Mathlib/CategoryTheory/Monoidal/Functor/Types.lean,Mathlib/CategoryTheory/Monoidal/Types/Coyoneda.lean,Mathlib/CategoryTheory/Sites/CoversTop/Over.lean,Mathlib/Combinatorics/Additive/FreimanHom.lean,Mathlib/Computability/AkraBazzi/AkraBazzi.lean,Mathlib/Data/ENNReal/Action.lean,Mathlib/Data/ENat/Pow.lean,Mathlib/Data/Finsupp/Pointwise.lean,Mathlib/Data/FunLike/Basic.lean,Mathlib/Data/FunLike/Embedding.lean,Mathlib/Data/FunLike/Equiv.lean,Mathlib/Data/Int/Cast/Pi.lean,Mathlib/Data/List/Monad.lean,Mathlib/Data/NNRat/Lemmas.lean,Mathlib/Data/Nat/Lattice.lean,Mathlib/Data/Prod/Lex.lean,Mathlib/Data/Rat/Cast/Defs.lean,Mathlib/Data/Rat/Cast/OfScientific.lean,Mathlib/Data/Real/Archimedean.lean,Mathlib/Data/ZMod/IntUnitsPower.lean,Mathlib/GroupTheory/GroupAction/Embedding.lean,Mathlib/GroupTheory/IsPerfect.lean,Mathlib/GroupTheory/ResiduallyFinite.lean,Mathlib/LinearAlgebra/CliffordAlgebra/Star.lean,Mathlib/LinearAlgebra/Projectivization/Action.lean,Mathlib/LinearAlgebra/RootSystem/GeckConstruction/Semisimple.lean,Mathlib/MeasureTheory/Function/L2Space.lean,Mathlib/MeasureTheory/Integral/IntegralEqImproper.lean,Mathlib/MeasureTheory/Measure/Sub.lean,Mathlib/MeasureTheory/Measure/Typeclasses/ZeroOne.lean,Mathlib/NumberTheory/ModularForms/EisensteinSeries/E2/Transform.lean,Mathlib/NumberTheory/NumberField/ExistsRamified.lean,Mathlib/NumberTheory/Padics/PadicVal/Defs.lean,Mathlib/Order/ConditionallyCompleteLattice/Basic.lean,Mathlib/Order/Filter/FilterProduct.lean,Mathlib/Order/Heyting/Basic.lean,Mathlib/Order/Interval/Set/OrdConnected.lean,Mathlib/Order/Quotient.lean,Mathlib/Probability/Kernel/Deterministic.lean,Mathlib/RingTheory/Coalgebra/Convolution.lean,Mathlib/RingTheory/Flat/IsBaseChange.lean,Mathlib/RingTheory/HopfAlgebra/TensorProduct.lean,Mathlib/RingTheory/Ideal/GoingDown.lean,Mathlib/RingTheory/Ideal/GoingUp.lean,Mathlib/RingTheory/Ideal/Maximal.lean,Mathlib/RingTheory/Localization/Finiteness.lean,Mathlib/RingTheory/Noetherian/Defs.lean,Mathlib/RingTheory/QuasiFinite/Basic.lean,Mathlib/RingTheory/QuasiFinite/Polynomial.lean,Mathlib/RingTheory/QuasiFinite/Weakly.lean,Mathlib/RingTheory/Regular/ProjectiveDimension.lean,Mathlib/RingTheory/SimpleModule/Basic.lean,Mathlib/RingTheory/Smooth/Fiber.lean,Mathlib/RingTheory/TensorProduct/IsBaseChangeRightExact.lean,Mathlib/RingTheory/Unramified/LocalRing.lean,Mathlib/RingTheory/Valuation/Extension.lean,Mathlib/RingTheory/Valuation/IsTrivialOn.lean,Mathlib/SetTheory/Cardinal/Regular.lean,Mathlib/Tactic/Algebra/Lemmas.lean,Mathlib/Topology/Algebra/UniformMulAction.lean,Mathlib/Topology/CWComplex/Classical/Subcomplex.lean,Mathlib/Topology/EMetricSpace/Pi.lean,Mathlib/Topology/List.lean,Mathlib/Topology/MetricSpace/Pseudo/Pi.lean	100	7	['eric-wieser', 'github-actions', 'grunweg', 'marcelolynch', 'mathlib-merge-conflicts', 'urkud']	nobody	3-48794 3 days ago	3-48795 3 days ago	15-20152 15 days
34875	banrovegrie author:banrovegrie	feat(LinearAlgebra/Matrix): add Sherman-Morrison formula	Mathlib has the matrix determinant lemma (`det_add_replicateCol_mul_replicateRow` in SchurComplement.lean) but lacked the corresponding inverse formula. This PR fills that gap. - Add `Matrix.inv_add_vecMulVec`: Sherman-Morrison formula for `(A + uv^T)^{-1}` - Add `Matrix.inv_sub_vecMulVec`: subtraction variant - Add `Matrix.isUnit_det_add_vecMulVec`: invertibility under the formula's hypotheses ## Test plan - [x] `lake build` passes - [x] Lines within 100 char limit - [x] All declarations have docstrings Any specific AI usage?: Used Copilot for review purposes.	t-algebra new-contributor awaiting-author label:t-algebra$	135/0	Mathlib.lean,Mathlib/LinearAlgebra/Matrix/ShermanMorrison.lean	2	15	['Xxxjdjdid', 'banrovegrie', 'chrisflav', 'copilot-pull-request-reviewer', 'eric-wieser', 'github-actions', 'wwylele']	chrisflav assignee:chrisflav	1-77043 1 day ago	47-78120 47 days ago	69-2479 69 days
39416	AlexBrodbelt author:AlexBrodbelt	feat(Mathlib/Tactic/Group): Improved the group tactic	The `group` tactic is improved to: 1. Once simplification on the exponents is done, apply left and right cancellation. That is, to normalise expressions like `a * b = a * c` to `b * c` 2. Apply a post-processing where expression of the form `( · )^(-1)` are normalised to use the inversion notation `( · )⁻¹`. This allows immediately being able to use lemmas involving inversion which is how most lemmas are stated. There is another PR which adds some relevant tests. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta new-contributor WIP	42055/19934	.github/actions/get-mathlib-ci/action.yml,.github/workflows/build_template.yml,.github/workflows/lake_cache_shadow.yml,.github/workflows/nolints.yml,.github/workflows/pr_check_downstream.yml,Archive/Examples/Eisenstein.lean,Archive/Examples/IfNormalization/Result.lean,Archive/Examples/IfNormalization/WithoutAesop.lean,Archive/Imo/Imo1959Q2.lean,Archive/Imo/Imo1960Q2.lean,Archive/Imo/Imo1977Q6.lean,Archive/Imo/Imo1982Q3.lean,Archive/Imo/Imo1987Q1.lean,Archive/Imo/Imo1988Q6.lean,Archive/Imo/Imo1994Q1.lean,Archive/Imo/Imo1998Q2.lean,Archive/Imo/Imo2001Q5.lean,Archive/Imo/Imo2002Q3.lean,Archive/Imo/Imo2006Q3.lean,Archive/Imo/Imo2006Q5.lean,Archive/Imo/Imo2008Q2.lean,Archive/Imo/Imo2008Q3.lean,Archive/Imo/Imo2008Q4.lean,Archive/Imo/Imo2010Q5.lean,Archive/Imo/Imo2013Q5.lean,Archive/Imo/Imo2015Q6.lean,Archive/Imo/Imo2019Q2.lean,Archive/Imo/Imo2024Q1.lean,Archive/Imo/Imo2024Q2.lean,Archive/Imo/Imo2024Q3.lean,Archive/Imo/Imo2024Q5.lean,Archive/Imo/Imo2024Q6.lean,Archive/Kuratowski.lean,Archive/MinimalSheffer.lean,Archive/MiuLanguage/DecisionSuf.lean,Archive/Sensitivity.lean,Archive/Wiedijk100Theorems/AbelRuffini.lean,Archive/Wiedijk100Theorems/AreaOfACircle.lean,Archive/Wiedijk100Theorems/AscendingDescendingSequences.lean,Archive/Wiedijk100Theorems/BallotProblem.lean,Archive/Wiedijk100Theorems/CubingACube.lean,Cache/IO.lean,Counterexamples/CliffordAlgebraNotInjective.lean,Counterexamples/DimensionPolynomial.lean,Counterexamples/EulerSumOfPowers.lean,Counterexamples/InvertibleModuleNotIdeal.lean,Counterexamples/MapFloor.lean,Counterexamples/NowhereDifferentiable.lean,Counterexamples/Phillips.lean,Counterexamples/Pseudoelement.lean,Counterexamples/SorgenfreyLine.lean,Counterexamples/TopologistsSineCurve.lean,Counterexamples/ZeroDivisorsInAddMonoidAlgebras.lean,Mathlib.lean,Mathlib/Algebra/AffineMonoid/Embedding.lean,Mathlib/Algebra/AffineMonoid/Irreducible.lean,Mathlib/Algebra/Algebra/Basic.lean,Mathlib/Algebra/Algebra/Bilinear.lean,Mathlib/Algebra/Algebra/Epi.lean,Mathlib/Algebra/Algebra/Equiv.lean,Mathlib/Algebra/Algebra/NonUnitalHom.lean,Mathlib/Algebra/Algebra/NonUnitalSubalgebra.lean,Mathlib/Algebra/Algebra/Operations.lean,Mathlib/Algebra/Algebra/Pi.lean,Mathlib/Algebra/Algebra/Spectrum/Basic.lean,Mathlib/Algebra/Algebra/Spectrum/Quasispectrum.lean,Mathlib/Algebra/Algebra/Subalgebra/Basic.lean,Mathlib/Algebra/Algebra/Subalgebra/Centralizer.lean,Mathlib/Algebra/Algebra/Subalgebra/Lattice.lean,Mathlib/Algebra/Algebra/Subalgebra/Operations.lean,Mathlib/Algebra/Algebra/Subalgebra/Rank.lean,Mathlib/Algebra/Algebra/Subalgebra/Unitization.lean,Mathlib/Algebra/Algebra/Tower.lean,Mathlib/Algebra/Algebra/Unitization.lean,Mathlib/Algebra/BigOperators/Fin.lean,Mathlib/Algebra/BigOperators/Finprod.lean,Mathlib/Algebra/BigOperators/Finsupp/Basic.lean,Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean,Mathlib/Algebra/BigOperators/Group/Finset/Defs.lean,Mathlib/Algebra/BigOperators/Group/Finset/Piecewise.lean,Mathlib/Algebra/BigOperators/Group/List/Basic.lean,Mathlib/Algebra/BigOperators/Group/Multiset/Basic.lean,Mathlib/Algebra/BigOperators/Intervals.lean,Mathlib/Algebra/BigOperators/Module.lean,Mathlib/Algebra/BigOperators/Pi.lean,Mathlib/Algebra/BigOperators/Ring/Finset.lean,Mathlib/Algebra/Category/AlgCat/Basic.lean,Mathlib/Algebra/Category/AlgCat/FilteredColimits.lean,Mathlib/Algebra/Category/AlgCat/Limits.lean,Mathlib/Algebra/Category/CoalgCat/ComonEquivalence.lean,Mathlib/Algebra/Category/ContinuousCohomology/Basic.lean,Mathlib/Algebra/Category/Grp/AB.lean,Mathlib/Algebra/Category/Grp/Adjunctions.lean,Mathlib/Algebra/Category/Grp/Biproducts.lean,Mathlib/Algebra/Category/Grp/Colimits.lean,Mathlib/Algebra/Category/Grp/EpiMono.lean,Mathlib/Algebra/Category/Grp/Kernels.lean,Mathlib/Algebra/Category/Grp/LargeColimits.lean,Mathlib/Algebra/Category/Grp/LeftExactFunctor.lean,Mathlib/Algebra/Category/Grp/Yoneda.lean	4358	4	['AlexBrodbelt', 'github-actions', 'mathlib-merge-conflicts']	nobody	0-60926 16 hours ago	unknown	unknown
40025	artie2000 author:artie2000	chore(Data/SetLike/Basic): generalise instance	* Generalise the standard `IsConcreteLE` instance from `PartialOrder.ofSetLike` to `LE.ofSetLike` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data	8/4	Mathlib/Data/SetLike/Basic.lean	1	4	['github-actions', 'leanprover-radar', 'vihdzp']	nobody	0-55452 15 hours ago	3-74176 3 days ago	3-73926 3 days
38649	chrisflav author:chrisflav	chore(RingTheory): equality of linear map with values in finite module spreads out	We add some corollaries of `Module.Finite.exists_smul_of_comp_eq_of_isLocalizedModule`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory large-import	75/1	Mathlib/Algebra/Module/FinitePresentation.lean,Mathlib/RingTheory/Localization/BaseChange.lean,Mathlib/RingTheory/Localization/Module.lean	3	2	['github-actions']	nobody	0-50149 13 hours ago	35-401 35 days ago	35-151 35 days
40152	BryceT233 author:BryceT233	feat(Algebra/Ring/Subring): units in `RingHom.eqLocus`	This PR is a split of #37008. @riccardobrasca --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra large-import delegated label:t-algebra$	14/0	Mathlib/Algebra/Ring/Subring/Units.lean	1	5	['BryceT233', 'github-actions', 'mathlib-bors', 'riccardobrasca']	nobody	0-2311 38 minutes ago	unknown	unknown

PRs looking for help

Number	Author	Title	Description	Labels	+/-	Modified files (first 100)	📝	💬	All users who commented or reviewed	Assignee(s)	Updated	Last status change	total time in review
8961	eric-wieser author:eric-wieser	refactor: use the coinduced topology on ULift	--- - [x] depends on: #8958 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict awaiting-author awaiting-CI	46/14	Mathlib/Analysis/Normed/Group/Basic.lean,Mathlib/Topology/Bornology/Constructions.lean,Mathlib/Topology/Constructions.lean	3	6	['eric-wieser', 'github-actions', 'leanprover-community-mathlib4-bot', 'urkud']	nobody	671-24112 1 year ago	unknown	unknown
9642	eric-wieser author:eric-wieser	refactor(Analysis/Normed/{Group/Field}/Basic): Let `extends` generate the repeated fields	New-style structure shenanigans mean that instance constructors randomly complain about a missing field that can be found with `__ : MetricSpace _ := infer_instance`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) I will write a longer PR description for this once CI is happy	WIP merge-conflict awaiting-author help-wanted t-analysis	122/202	Mathlib/Analysis/Calculus/ContDiff/Basic.lean,Mathlib/Analysis/Complex/Basic.lean,Mathlib/Analysis/Matrix.lean,Mathlib/Analysis/Normed/Field/Basic.lean,Mathlib/Analysis/Normed/Group/Basic.lean,Mathlib/Analysis/Normed/Group/Completion.lean,Mathlib/Analysis/Normed/Order/Basic.lean,Mathlib/Analysis/NormedSpace/ProdLp.lean,Mathlib/Analysis/NormedSpace/Star/Matrix.lean,Mathlib/Analysis/NormedSpace/Unitization.lean,Mathlib/Analysis/Quaternion.lean,Mathlib/Geometry/Manifold/Instances/Sphere.lean,Mathlib/InformationTheory/Hamming.lean,Mathlib/MeasureTheory/Measure/Lebesgue/VolumeOfBalls.lean,Mathlib/NumberTheory/NumberField/CanonicalEmbedding.lean,Mathlib/NumberTheory/Padics/PadicIntegers.lean,Mathlib/Topology/ContinuousFunction/Bounded.lean	17	11	['eric-wieser', 'leanprover-bot', 'urkud']	nobody	671-24112 1 year ago	unknown	unknown
6791	eric-wieser author:eric-wieser	refactor: Use flat structures for morphisms	This restores the symmetry we had in Lean3, where we had `MonoidHom.mk f one mul` not `MonoidHom.mk (OneHom.mk f one) mul`, and `f.toFun` wasn't notation for `f.toMulHom.toFun`. The nesting provided by the previous inheritance is useless to us in the face of `MonoidHomClass.toMonoidHom`, which completely eta-expands the structure anyway. We call the class `FunLikeFlatHack._` because this means the field is called `to_` which uses up less space in the goal view than any alternative. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author help-wanted awaiting-CI	174/201	Mathlib/Algebra/Algebra/Equiv.lean,Mathlib/Algebra/Algebra/Hom.lean,Mathlib/Algebra/Category/GroupCat/ZModuleEquivalence.lean,Mathlib/Algebra/Category/GroupWithZeroCat.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf.lean,Mathlib/Algebra/Category/MonCat/Basic.lean,Mathlib/Algebra/Group/Ext.lean,Mathlib/Algebra/Group/Prod.lean,Mathlib/Algebra/Group/UniqueProds.lean,Mathlib/Algebra/Hom/Equiv/Basic.lean,Mathlib/Algebra/Hom/Group/Defs.lean,Mathlib/Algebra/Hom/GroupAction.lean,Mathlib/Algebra/Hom/NonUnitalAlg.lean,Mathlib/Algebra/Hom/Ring/Defs.lean,Mathlib/Algebra/Lie/Basic.lean,Mathlib/Algebra/Module/Equiv.lean,Mathlib/Algebra/Module/LinearMap.lean,Mathlib/Algebra/Order/Hom/Ring.lean,Mathlib/Algebra/Order/Interval.lean,Mathlib/Algebra/Ring/Equiv.lean,Mathlib/Analysis/Normed/Group/SemiNormedGroupCat.lean,Mathlib/Data/FunLike/Basic.lean,Mathlib/Data/Rat/Cast/CharZero.lean,Mathlib/Data/Real/EReal.lean,Mathlib/Data/Real/Sqrt.lean,Mathlib/GroupTheory/FreeAbelianGroup.lean,Mathlib/GroupTheory/MonoidLocalization.lean,Mathlib/LinearAlgebra/Quotient.lean,Mathlib/LinearAlgebra/TensorProduct.lean,Mathlib/RingTheory/RingInvo.lean,Mathlib/Topology/Algebra/Module/Basic.lean,Mathlib/Topology/MetricSpace/Dilation.lean	32	0	[]	nobody	671-24111 1 year ago	unknown	unknown
6931	urkud author:urkud	refactor(Analysis/Normed): use `RingHomIsometric` for `.norm_cast`	--- I don't understand why linter fails. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict help-wanted t-analysis	78/68	Mathlib/Analysis/LocallyConvex/ContinuousOfBounded.lean,Mathlib/Analysis/Normed/Field/Basic.lean,Mathlib/Analysis/Normed/Group/Basic.lean,Mathlib/Analysis/NormedSpace/Basic.lean,Mathlib/Analysis/NormedSpace/Exponential.lean,Mathlib/Analysis/NormedSpace/Spectrum.lean,Mathlib/Analysis/RCLike/Basic.lean,Mathlib/NumberTheory/NumberField/Embeddings.lean	8	0	[]	nobody	671-24111 1 year ago	unknown	unknown
7903	urkud author:urkud	feat: define `UnboundedSpace`	--- The new instances generate some timeouts, and I don't understand why. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict help-wanted t-topology	111/59	Mathlib/Analysis/BoxIntegral/Basic.lean,Mathlib/Analysis/Normed/Module/Basic.lean,Mathlib/Topology/Bornology/Basic.lean,Mathlib/Topology/Bornology/Constructions.lean,Mathlib/Topology/MetricSpace/Bounded.lean,Mathlib/Topology/MetricSpace/GromovHausdorffRealized.lean	6	1	['github-actions']	nobody	664-12088 1 year ago	unknown	unknown
9973	Ruben-VandeVelde author:Ruben-VandeVelde	feat: polynomials formed by lists	From https://github.com/leanprover-community/mathlib/pull/15476 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict t-data	311/0	Mathlib.lean,Mathlib/Data/Polynomial/OfList.lean	2	0	[]	nobody	657-17188 1 year ago	unknown	unknown
9444	erdOne author:erdOne	feat: Various instances regarding `𝓞 K`.	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict help-wanted t-number-theory	27/0	Mathlib/NumberTheory/NumberField/Basic.lean,Mathlib/RingTheory/IntegralClosure.lean	2	9	['erdOne', 'leanprover-bot', 'mattrobball', 'riccardobrasca', 'xroblot']	nobody	656-13864 1 year ago	unknown	unknown
20656	Komyyy author:Komyyy	feat(Mathlib/Geometry/Manifold/VectorBundle/Sphere): convert orthogonal smooth `M → 𝕊ⁿ` & `M → ℝⁿ⁺¹` to smooth `M → T𝕊ⁿ`	Current Mathlib has no easy way to define function from a manifold to tangent bundles of sphere: `T𝕊ⁿ`. This PR gives this: `sphereTangentMap`. This convert orthogonal smooth `M → 𝕊ⁿ` & `M → ℝⁿ⁺¹` to smooth `M → T𝕊ⁿ`. I also proved that if `f : M → 𝕊ⁿ` & `g : M → ℝⁿ⁺¹` are smooth then `sphereTangentMap` of `f` & `g` is smooth too. --- ⚠ CAUTION I formalized this in my spare time. I don't have the energy to maintain the PR, but I create this PR so this may helps everyone. The only one thing to do is proof cleanup. TODO: - [x] `contDiff_uncurry_stereoInvFunAux` & `coe_sphere_comp_stereoInvFun` may have to be moved to `Mathlib.Geometry.Manifold.Instances.Sphere`. - [ ] Proof cleanup. Current proof may be redundant and ugly. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict t-differential-geometry	246/6	Mathlib.lean,Mathlib/Geometry/Manifold/Instances/Sphere.lean,Mathlib/Geometry/Manifold/VectorBundle/Sphere.lean	3	1	['github-actions']	nobody	502-21888 1 year ago	unknown	unknown
11837	trivial1711 author:trivial1711	feat: completion of a uniform multiplicative group	Multiplicativize `Topology.Algebra.GroupCompletion`. That is, rewrite it in the multiplicative setting and recover the original results using `@[to_additive]`. - Because `@[to_additive]` doesn't work with `noncomputable section` (https://github.com/leanprover/lean4/pull/2610), some instances with `@[to_additive]` need to be explicitly marked with `noncomputable instance`. - One might be tempted to multiplicativize this definition from `Topology.Algebra.GroupCompletion`: ```lean instance [UniformSpace α] [Add α] : Add (Completion α) := ⟨Completion.map₂ (· + ·)⟩ ``` to this: ```lean @[to_additive] instance [UniformSpace α] [Mul α] : Mul (Completion α) := ⟨Completion.map₂ (· * ·)⟩ ``` However, as Eric Wieser pointed out, doing so would create a bad diamond with the definition ```lean instance [UniformSpace α] [TopologicalRing α] [UniformAddGroup α] [Ring α] : Mul (Completion α) := ⟨curry <\| (denseInducing_coe.prod denseInducing_coe).extend ((↑) ∘ uncurry (· * ·))⟩ ``` in `Topology.Algebra.UniformRing`. How should this diamond be resolved? Well, the definition of multiplication that uses `curry <\| (denseInducing_coe.prod denseInducing_coe).extend ((↑) ∘ uncurry (· * ·))` is the "correct" one. For example, it yields the correct result if `α` is `ℚ`, unlike the definition that uses `Completion.map₂ (· * ·)`. (This is because `Completion.map₂` yields junk values if used on a function which is not uniformly continuous. Note, however, that if multiplication on `α` is uniformly continuous, then `Completion.map₂ (· * ·)` and `curry <\| (denseInducing_coe.prod denseInducing_coe).extend ((↑) ∘ uncurry (· * ·))` are propositionally equal.) So, following Eric's suggestion, we remove the definition that uses `Completion.map₂ (· * ·)`, and generalize the other definition to any uniform space with a multiplication operation: ```lean @[to_additive] noncomputable instance [UniformSpace α] [Mul α] : Mul (Completion α) := ⟨curry <\| (denseInducing_coe.prod denseInducing_coe).extend ((↑) ∘ uncurry (· * ·))⟩ ``` This requires slightly modifying some of the proofs in `Topology.Algebra.GroupCompletion`. For example, suppose that `α` is a uniform group. Since we can no longer use `Completion.continuous_map₂`, it becomes more efficient to prove that the multiplication, inversion, and division operations on `Completion α` are uniformly continuous before we prove that `Completion α` is a group. - Previously, `Topology.Algebra.GroupCompletion` had an instance: ```lean instance [UniformSpace α] [Sub α] : Sub (Completion α) := ... ``` Naively multiplicativizing this would yield ```lean @[to_additive] instance [UniformSpace α] [Inv α] : Inv (Completion α) := ... ``` Unfortunately, this would conflict with `Topology.Algebra.UniformField`, which already instantiates `Inv (Completion α)` when `α` is a uniform field. Instead, we use two different `instance` declarations. (If `α` is an additive group, then this instantiates `Neg (Completion α)` twice, and the instances are syntactically equal.) ```lean @[to_additive] noncomputable instance [UniformSpace α] [Group α] : Inv (Completion α) := ... instance [UniformSpace α] [Neg α] : Neg (Completion α) := ... ``` This avoids the bad diamond (because a uniform field can never be a `Group`) while remaining backward compatible. Note that the `@[to_additive]` is necessary here, because it maintains the link between the additive setting and multiplicative setting. We use a similar method to instantiate `Div (Completion α)`. - Some definitions in this file involve a module structure on `α`. We leave these as is and do not attempt to multiplicativize them at all. - The instance of `DistribMulAction` must be multiplicativized to an instance of `MulDistribMulAction` manually. Zulip thread: https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/Completion.20of.20a.20uniform.20multiplicative.20group --- # (Small) Issue Recall the following trick that this pull request uses to define inversion and negation on uniform spaces. The idea is that we define negation on the completion of any uniform space that has a negation operation, but we define inversion on only the completion of a uniform space that has the structure of a multiplicative group. We do this to avoid creating a bad diamond with the inversion operation on a uniform field. ```lean @[to_additive] noncomputable instance {α : Type} [UniformSpace α] [Group α] : Inv (Completion α) := ... instance {α : Type} [UniformSpace α] [Neg α] : Neg (Completion α) := ... ``` Now, suppose that we want to prove `coe_inv_of_group` (resp. `coe_neg`), which states that the coercion `α → Completion α` commutes with inversion (resp. negation). In the current version of this pull request, `coe_inv_of_group` (resp. `coe_neg`) only applies to uniform multiplicative (resp. additive) groups. However, we do not use the fact that multiplication (resp. addition) on `α` is uniformly continuous to prove it. We only use the fact that inversion (resp. negation) is continuous. So, what we really want is to have more general statements that look like this: ```lean theorem coe_inv_of_group {α : Type} [UniformSpace α] [Group α] [ContinuousInv α] : ... theorem coe_neg {α : Type} [UniformSpace α] [Neg α] [ContinuousNeg α] : ... ``` Note that `coe_inv_of_group` needs the assumption `[Group α]`, because otherwise inversion is not defined on `Completion α` at all. However, `coe_neg` does not need the analogous assumption `[AdditiveGroup α]`. The question is: If `coe_inv_of_group` and `coe_neg` are written in this more general form, how can we link them using `@[to_additive]`? Here is one option, but it obviously leaves something to be desired. ```lean @[to_additive coe_neg_do_not_use_this_use_the_more_general_version] theorem coe_inv_of_group {α : Type} [UniformSpace α] [Group α] [ContinuousInv α] : ... theorem coe_neg {α : Type} [UniformSpace α] [Neg α] [ContinuousNeg α] : ... ``` Co-authored-by: Eric Wieser --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-algebra merge-conflict help-wanted t-topology label:t-algebra$	342/217	Mathlib/Analysis/InnerProductSpace/Completion.lean,Mathlib/Analysis/Normed/Group/HomCompletion.lean,Mathlib/Analysis/Normed/Module/Completion.lean,Mathlib/Topology/Algebra/GroupCompletion.lean,Mathlib/Topology/Algebra/InfiniteSum/GroupCompletion.lean,Mathlib/Topology/Algebra/Nonarchimedean/Completion.lean,Mathlib/Topology/Algebra/UniformField.lean,Mathlib/Topology/Algebra/UniformMulAction.lean,Mathlib/Topology/Algebra/UniformRing.lean	9	14	['eric-wieser', 'github-actions', 'trivial1711']	nobody	487-65709 1 year ago	unknown	unknown
7994	ericrbg author:ericrbg	chore: generalize `LieSubalgebra.mem_map_submodule`	--- Not sure if we should rename to something like `mem_map_iff_mem_map_submodule` or not. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict t-algebra label:t-algebra$	16/4	Mathlib/Algebra/Lie/SkewAdjoint.lean,Mathlib/Algebra/Lie/Subalgebra.lean	2	3	['eric-wieser', 'ericrbg']	nobody	395-25787 1 year ago	unknown	unknown
15115	kkytola author:kkytola	feat: Generalize assumptions in liminf and limsup results in ENNReals	In a [review comment](https://github.com/leanprover-community/mathlib4/pull/13938#discussion_r1649744441) it was pointed out that results about liminf and limsup in ENNReal hold under milder assumptions. This PR does the generalization. --- This PR is split off from #13938, where the review comment was made. The changes needed for the suggested generalization were of different kind than the simple PR's content, justifying a separate PR. - [x] depends on: #13938 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order merge-conflict help-wanted awaiting-author t-topology	215/27	Mathlib/MeasureTheory/Measure/Portmanteau.lean,Mathlib/Order/LiminfLimsup.lean,Mathlib/Topology/Instances/ENNReal.lean	3	8	['Ruben-VandeVelde', 'github-actions', 'grunweg', 'j-loreaux', 'kkytola', 'leanprover-community-mathlib4-bot']	nobody	383-7164 1 year ago	unknown	unknown
12799	jstoobysmith author:jstoobysmith	feat(LinearAlgebra/UnitaryGroup): Add properties of Special Unitary Group	Add properties of the special unitary group, mirroring the properties of found in Algebra/Star/Unitary.lean. In particular, I add an instance of `specialUnitaryGroup` as a `Group`, `Star`, `InvolutiveStar`, and `StarMul`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt t-algebra new-contributor merge-conflict awaiting-author label:t-algebra$	78/0	Mathlib/LinearAlgebra/UnitaryGroup.lean	1	8	['chrisflav', 'jcommelin', 'leanprover-community-bot-assistant']	nobody	360-49083 11 months ago	unknown	unknown
7300	ah1112 author:ah1112	feat: synthetic geometry	This is adding synthetic geometry using Avigad's axioms and formalizing Euclid Book I, through the Pythagorean theorem. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author help-wanted t-euclidean-geometry	2661/0	Mathlib.lean,Mathlib/Geometry/Synthetic/Avigad/Axioms.lean,Mathlib/Geometry/Synthetic/Avigad/EuclidBookI.lean,Mathlib/Geometry/Synthetic/Avigad/Tactics.lean	4	74	['ah1112', 'alreadydone', 'eric-wieser', 'github-actions', 'leanprover-community-bot-assistant', 'plp127', 'tb65536', 'urkud']	nobody	284-46925 9 months ago	unknown	unknown
26085	grunweg author:grunweg	feat: disjoint unions distribute with products of manifolds	This PR continues the work from #22611. Original PR: https://github.com/leanprover-community/mathlib4/pull/22611	please-adopt WIP t-differential-geometry merge-conflict	75/6	Mathlib/Geometry/Manifold/Diffeomorph.lean,Mathlib/Geometry/Manifold/LocalDiffeomorph.lean	2	3	['github-actions', 'grunweg', 'mathlib4-merge-conflict-bot']	nobody	214-16254 7 months ago	unknown	unknown
5863	eric-wieser author:eric-wieser	feat: add elaborators for concrete matrices	--- - [x] depends on: #5866 - [ ] depends on: #5897 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict help-wanted blocked-by-other-PR t-meta	257/7	Mathlib/Control/Monad/Cont.lean,Mathlib/Data/Matrix/Auto.lean,MathlibTest/matrix_auto.lean	3	8	['eric-wieser', 'github-actions', 'kim-em', 'leanprover-community-bot-assistant', 'mathlib4-merge-conflict-bot']	nobody	195-26957 6 months ago	unknown	unknown
5919	MithicSpirit author:MithicSpirit	feat: implement orthogonality for AffineSubspace	Define `AffineSubspace.orthogonal` and `AffineSubspace.IsOrtho`, as well as develop an API emulating that of `Submodule.orthogonal` and `Submodule.IsOrtho`, respectively. Additionally, provide some relevant lemmas exclusive to affine subspaces, which are mostly to do with the relationship between orthogonality and `AffineSubspace.Parallel`. Closes #5539 --- Still WIP as I need to add more docstrings as well as notations for the new definitions. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP new-contributor merge-conflict help-wanted t-analysis	287/0	Mathlib.lean,Mathlib/Analysis/InnerProductSpace/AffineSubspace.lean	2	7	['MithicSpirit', 'eric-wieser', 'github-actions', 'leanprover-community-bot-assistant', 'mathlib4-merge-conflict-bot']	MithicSpirit assignee:MithicSpirit	195-26956 6 months ago	unknown	unknown
13442	dignissimus author:dignissimus	feat: mabel tactic for multiplicative abelian groups	Mabel tactic for multiplicative abelian groups (#10361) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict modifies-tactic-syntax awaiting-author help-wanted t-meta	439/0	Mathlib.lean,Mathlib/Tactic.lean,Mathlib/Tactic/MAbel.lean,MathlibTest/mabel.lean	4	11	['BoltonBailey', 'dignissimus', 'github-actions', 'joneugster', 'kbuzzard', 'mathlib4-merge-conflict-bot']	joneugster assignee:joneugster	195-26692 6 months ago	unknown	unknown
26398	ChrisHughes24 author:ChrisHughes24	feat(ModelTheory): definable functions	--- Possibly this should be generalized to partial functions. I migrated the PR by hand instead of using the script. - [x] depends on: #20166 - [x] depends on: #20161 - [x] depends on: #20115 - [x] depends on: #20174 - [x] depends on: #20175 - [x] depends on: #21948 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict t-logic	618/0	Mathlib.lean,Mathlib/ModelTheory/FunctionalFormula.lean	2	13	['ChrisHughes24', 'github-actions', 'jcommelin', 'kckennylau', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'staroperator']	nobody	195-25568 6 months ago	217-15033 217 days ago	87-75972 87 days
29675	yury-harmonic author:yury-harmonic	feat(Wolstenholme): new file	Co-authored-by: @Aristotle-Harmonic --- I still need to cleanup the proof and write the docs. For now, it's just what the AI generated, forward-ported to the latest Mathlib. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author help-wanted t-data	198/0	Mathlib.lean,Mathlib/Data/Nat/Choose/Wolstenholme.lean	2	5	['Alex-Linhares', 'github-actions', 'mathlib4-merge-conflict-bot', 'yury-harmonic']	nobody	195-24344 6 months ago	unknown	unknown
6859	MohanadAhmed author:MohanadAhmed	feat: TryLean4Bundle: Windows Bundle Creator	# `TryLean4Bundle`: Windows Bundle Creator A Windows batch script and a CI yml file that create an self extracting archive. The user should 1. just download the archive, 2. double click the archive to expand 3. double click the `RunLean.bat` script in the expanded archive. The script currently downloads 7 dependencies into CI then unpacks them in the appropriate locations and finally packs them back. To try a bundle created using these scripts but from a different repo see (https://github.com/MohanadAhmed/TryLean4Bundle/releases) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP help-wanted CI	114/0	.github/workflows/mk_windows_bundle.yml,scripts/windowsBundle.bat	2	0	[]	nobody	194-84669 6 months ago	unknown	unknown
11800	JADekker author:JADekker	feat: KappaLindelöf spaces	Define KappaLindelöf spaces by following the first one-third of the API for Lindelöf spaces. The remainder will be added in a future PR. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict t-topology awaiting-zulip	301/2	Mathlib.lean,Mathlib/Topology/Compactness/KappaLindelof.lean,Mathlib/Topology/Compactness/Lindelof.lean	3	38	['ADedecker', 'JADekker', 'PatrickMassot', 'StevenClontz', 'adomani', 'github-actions', 'grunweg', 'kim-em', 'urkud']	nobody	194-84533 6 months ago	unknown	unknown
12087	JADekker author:JADekker	feat: complete API for K-Lindelöf spaces	--- - [ ] depends on: #11800 (which is now awaiting a design decision) [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict t-topology blocked-by-other-PR	789/17	Mathlib.lean,Mathlib/Order/Filter/CardinalInter.lean,Mathlib/Topology/Compactness/KLindelof.lean,Mathlib/Topology/Compactness/Lindelof.lean	4	2	['github-actions', 'leanprover-community-mathlib4-bot']	nobody	194-84526 6 months ago	unknown	unknown
12394	JADekker author:JADekker	feat: define pre-tight and tight measures	Define tight measures (by first defining separable and pre-tight measures). Define some api for all three concepts Prove Ulam's tightness theorem and a strengthened version of this. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict awaiting-author t-measure-probability	503/0	Mathlib.lean,Mathlib/MeasureTheory/Measure/Tight.lean	2	34	['EtienneC30', 'JADekker', 'github-actions', 'sgouezel']	nobody	194-84506 6 months ago	unknown	unknown
14686	smorel394 author:smorel394	feat(AlgebraicGeometry/Grassmannian): define the Grassmannian scheme	# The Grassmannian scheme Define the Grassmannian scheme by gluing affine charts. We fix a commutative ring `K`, a free `K`-module of finite type `V` and two natural numbers `r` and `c`. The scheme we define should parametrize surjective `K`-linear maps `V →ₗ[K] (Fin r → K)`, assuming that `V` is of rank `r + c`. We actually define the scheme without assuming the condition on the rank of `V`, but it is empty unless the rank of `V` is `r + c`. Main definitions: * `Grassmannian.glueData K V r c`: the `AlgebraicGeometry.Scheme.GlueData` defining the Grassmannian scheme. * `Grassmannian K V r c`: the Grassmannian scheme, defined as `(Grassmannian.glueData K V r c).glued`. * `Grassmannian.structMorphism K V r c`: the structural morphism from `Grassmannian K V r c` to `Spec K`. # Implementation We use as index type for the charts the type `Basis (Fin (r + c)) K V` (so this is empty unless `V` is free of rank `r + c`). All the charts are the same and equal to the affine space with coordinates indexed by `Fin c × Fin r`, that is, to `Spec (MvPolynomial (Fin c × Fin r) K)`. The idea is that, for `i` in `Basis (Fin (r + c)) K V`, the corresponding chart will parametrize all surjective `K`-linear maps `φ : V →ₗ[K] (Fin r → K)` that become isomorphisms when restricted to the `K`-submodule generated by the first `r` vectors of the basis `i`. To get the point of the chart corresponding to `φ`, we take the matrix of `φ` in the basis `i` of `V` and the canonical basis of `Fin r → K`, we divide it on the right by its top `r × r` square submatrix (which is invertible by assumption), and we taken the botton `c × r` submatrix. This is almost the usual description of the Grassmannian by charts, with three differences: * We consider the Grassmannian parametrizing `r`-dimensional quotients of `V` instead of `r`-dimensional subspaces of `V`, because this is more natural when working over a general ring (or scheme). * In the usual description, we fix a basis of `V` and index the chart by its subsets `I` of cardinality `r`. Here, to avoid making a choice, we instead index charts by the set of bases of `V` and always choose the subset `I` to consist of the first `r` vectors. * Instead of working with `FiniteDimensional.finrank K V - r`, which would cause technical trouble because of the way subtraction works on `ℕ`, we introduce the codimension `c` as an auxiliary variable, and our constructions are only interesting when `r + c` is equal to `FiniteDimensional.finrank K V`. # Why is this a WIP * There a bunch of lemmas in the file `AlgebraicGeometry/Grassmannian/Lemmas.lean` that either should not be necessary or should be put in another PR for some other part of mathlib. * The proofs in `AlgebraicGeometry/Grassmannian/Basic.lean` are probably too complicated, and the names suck. # Notes. This contribution was created as part of the AIM workshop "Formalizing algebraic geometry" in June 2024. --- - [x] depends on: #14711 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt WIP workshop-AIM-AG-2024 merge-conflict t-algebraic-geometry	1002/0	Mathlib.lean,Mathlib/AlgebraicGeometry/Grassmannian/Basic.lean,Mathlib/AlgebraicGeometry/Grassmannian/Lemmas.lean	3	15	['erdOne', 'github-actions', 'joelriou', 'leanprover-community-mathlib4-bot', 'smorel394']	nobody	194-84462 6 months ago	unknown	unknown
32095	grunweg author:grunweg	chore: fix some explicitVarOfIff linter errors	Needs a merge, and removing the linter changes... should be re-done and split out! --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt WIP merge-conflict	320/146	Mathlib/Analysis/LocallyConvex/Bounded.lean,Mathlib/Analysis/Oscillation.lean,Mathlib/Geometry/Manifold/LocalInvariantProperties.lean,Mathlib/MeasureTheory/Measure/EverywherePos.lean,Mathlib/SetTheory/Ordinal/Topology.lean,Mathlib/Topology/Algebra/Group/Basic.lean,Mathlib/Topology/Algebra/Module/Basic.lean,Mathlib/Topology/Algebra/Monoid.lean,Mathlib/Topology/Bases.lean,Mathlib/Topology/Basic.lean,Mathlib/Topology/Category/TopCat/Basic.lean,Mathlib/Topology/Clopen.lean,Mathlib/Topology/CompactOpen.lean,Mathlib/Topology/Compactness/LocallyCompact.lean,Mathlib/Topology/Constructions.lean,Mathlib/Topology/ContinuousOn.lean,Mathlib/Topology/DenseEmbedding.lean,Mathlib/Topology/Gluing.lean,Mathlib/Topology/Homeomorph.lean,Mathlib/Topology/IndicatorConstPointwise.lean,Mathlib/Topology/Inseparable.lean,Mathlib/Topology/Irreducible.lean,Mathlib/Topology/IsLocalHomeomorph.lean,Mathlib/Topology/LocalAtTarget.lean,Mathlib/Topology/Maps/Basic.lean,Mathlib/Topology/MetricSpace/Isometry.lean,Mathlib/Topology/NoetherianSpace.lean,Mathlib/Topology/Order.lean,Mathlib/Topology/Order/LowerUpperTopology.lean,Mathlib/Topology/Partial.lean,Mathlib/Topology/PartialHomeomorph.lean,Mathlib/Topology/PartitionOfUnity.lean,Mathlib/Topology/QuasiSeparated.lean,Mathlib/Topology/Separation.lean,Mathlib/Topology/TietzeExtension.lean,Mathlib/Topology/UniformSpace/Ascoli.lean,Mathlib/Topology/UniformSpace/Basic.lean,Mathlib/Topology/UniformSpace/Cauchy.lean,Mathlib/Topology/UniformSpace/CompactConvergence.lean,Mathlib/Topology/UniformSpace/Completion.lean,Mathlib/Topology/UniformSpace/Equicontinuity.lean,Mathlib/Topology/UniformSpace/Matrix.lean,Mathlib/Topology/UniformSpace/Pi.lean,Mathlib/Topology/UnitInterval.lean,Mathlib/Topology/UrysohnsBounded.lean,Mathlib/Topology/UrysohnsLemma.lean,Mathlib/Topology/VectorBundle/Basic.lean,lakefile.lean,scripts/run_linter.lean	49	0	[]	nobody	189-11578 6 months ago	unknown	unknown
5934	eric-wieser author:eric-wieser	feat: port Data.Rat.MetaDefs	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) This needs some eyes from people familiar with Qq	merge-conflict help-wanted mathlib-port t-meta	183/0	Mathlib.lean,Mathlib/Data/Rat/MetaDefs.lean,test/rat.lean	3	5	['eric-wieser', 'gebner', 'vihdzp']	nobody	157-71995 5 months ago	unknown	unknown
21344	kbuzzard author:kbuzzard	chore: attempt to avoid diamond in OreLocalization	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt t-algebra label:t-algebra$	16/5	Mathlib/RingTheory/OreLocalization/Basic.lean	1	6	['erdOne', 'github-actions', 'kbuzzard']	nobody	148-60683 4 months ago	unknown	unknown
17176	arulandu author:arulandu	feat: integrals and integrability with .re	Lemmas for swapping order of .re and integration/integrability. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author new-contributor t-measure-probability please-adopt	49/0	Mathlib/MeasureTheory/Function/L1Space.lean,Mathlib/MeasureTheory/Integral/IntegrableOn.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral.lean,Mathlib/MeasureTheory/Integral/SetIntegral.lean	4	32	['EtienneC30', 'arulandu', 'github-actions', 'loefflerd']	nobody	147-68098 4 months ago	unknown	unknown
24010	grunweg author:grunweg	feat(Counterexamples): a non-negative function, not a.e. zero, with vanishing lowe…	…r Lebesgue integral. Came up in #23707, let's document this while we're at it. --- - [ ] depends on: #20722 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict please-adopt WIP blocked-by-other-PR t-measure-probability	110/0	Counterexamples.lean,Counterexamples/LIntegralZero.lean	2	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	145-6328 4 months ago	unknown	unknown
25905	mans0954 author:mans0954	feat(RingTheory/Polynomial/SmallDegreeVieta): polynomial versions of results in Algebra.QuadraticDiscriminant	This PR continues the work from #25605. Original PR: https://github.com/leanprover-community/mathlib4/pull/25605	merge-conflict t-ring-theory please-adopt	77/8	Mathlib/Algebra/Polynomial/Coeff.lean,Mathlib/RingTheory/Polynomial/SmallDegreeVieta.lean	2	47	['chrisflav', 'github-actions', 'kckennylau', 'mans0954', 'mathlib4-merge-conflict-bot', 'ocfnash']	chrisflav assignee:chrisflav	142-56991 4 months ago	268-85370 268 days ago	81-70379 81 days
26339	mans0954 author:mans0954	feat(Analysis/Normed/Module/WeakDual): Banach Dieudonné Lemma	This PR continues the work from #16316. Original PR: https://github.com/leanprover-community/mathlib4/pull/16316	merge-conflict WIP t-analysis large-import please-adopt	377/3	Mathlib/Analysis/LocallyConvex/AbsConvex.lean,Mathlib/Analysis/LocallyConvex/Polar.lean,Mathlib/Analysis/Normed/Module/WeakDual.lean,Mathlib/Topology/UniformSpace/Cauchy.lean	4	5	['github-actions', 'mans0954', 'mathlib4-merge-conflict-bot']	nobody	142-56952 4 months ago	unknown	unknown
26340	mans0954 author:mans0954	feat(Algebra/Module/NestAlgebra): Nest algebras	This PR continues the work from #18705. Original PR: https://github.com/leanprover-community/mathlib4/pull/18705	merge-conflict t-algebra please-adopt label:t-algebra$	184/0	Mathlib.lean,Mathlib/Algebra/Module/NestAlgebra.lean,Mathlib/Order/Nest.lean,Mathlib/Order/Preorder/Chain.lean,docs/references.bib	5	3	['github-actions', 'mans0954', 'mathlib4-merge-conflict-bot']	nobody	142-56936 4 months ago	unknown	unknown
26341	mans0954 author:mans0954	feat(LinearAlgebra/QuadraticForm/Basis): Free Tensor product of Quadratic Maps	This PR continues the work from #19432. Original PR: https://github.com/leanprover-community/mathlib4/pull/19432	merge-conflict WIP t-algebra large-import please-adopt label:t-algebra$	888/0	Mathlib.lean,Mathlib/Data/Sym/Sym2/Prod.lean,Mathlib/LinearAlgebra/QuadraticForm/Basis.lean	3	3	['github-actions', 'mans0954', 'mathlib4-merge-conflict-bot']	nobody	142-56705 4 months ago	unknown	unknown
26344	mans0954 author:mans0954	feat(Analysis/NormedSpace/MStructure): The component projections on WithLp 1 (α × β) are L-projections	This PR continues the work from #20380. Original PR: https://github.com/leanprover-community/mathlib4/pull/20380	merge-conflict WIP t-analysis file-removed please-adopt	20/1	Mathlib.lean,Mathlib/Analysis/Normed/Lp/MStructure.lean,Mathlib/Analysis/Normed/Lp/ProdLp.lean	3	3	['github-actions', 'mans0954', 'mathlib4-merge-conflict-bot']	nobody	142-51501 4 months ago	unknown	unknown
26347	mans0954 author:mans0954	feat(Data/Finset/RangeDistance): abs_sub_lt_of_mem_finset_range	This PR continues the work from #23161. Original PR: https://github.com/leanprover-community/mathlib4/pull/23161	merge-conflict t-data please-adopt	30/0	Mathlib.lean,Mathlib/Algebra/Order/Group/Unbundled/Abs.lean,Mathlib/Data/Finset/RangeDistance.lean	3	3	['github-actions', 'mans0954', 'mathlib4-merge-conflict-bot']	alreadydone assignee:alreadydone	142-51478 4 months ago	195-25576 195 days ago	142-44021 142 days
26349	mans0954 author:mans0954	feat(Analysis/SpecialFunctions/Trigonometric/Basic): sin and cos of multiples of π / 3	This PR continues the work from #25009. Original PR: https://github.com/leanprover-community/mathlib4/pull/25009	help-wanted t-analysis please-adopt	159/0	Mathlib/Algebra/Order/Monoid/NatCast.lean,Mathlib/Analysis/SpecialFunctions/Trigonometric/Basic.lean,Mathlib/Data/Nat/Cast/Defs.lean,MathlibTest/trigonometry.lean	4	3	['github-actions', 'mans0954', 'themathqueen']	nobody	142-51434 4 months ago	unknown	unknown
26348	mans0954 author:mans0954	feat(Analysis/LocallyConvex/Prime): the prime map	This PR continues the work from #24385. Original PR: https://github.com/leanprover-community/mathlib4/pull/24385	merge-conflict WIP t-analysis please-adopt	125/0	Mathlib.lean,Mathlib/Analysis/LocallyConvex/Prime.lean	2	3	['github-actions', 'mans0954', 'mathlib4-merge-conflict-bot']	nobody	142-51425 4 months ago	unknown	unknown
26983	mans0954 author:mans0954	feat(Order/LatticeElements): distributive, standard and neutral elements of a lattice	Defines distributive, standard and neutral elements of a lattice and gives equivalent conditions. --- - [x] depends on: #26836 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP t-order please-adopt	238/0	Mathlib.lean,Mathlib/Order/Hom/Lattice.lean,Mathlib/Order/LatticeElements.lean	3	5	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	142-51392 4 months ago	239-75649 239 days ago	0-20134 5 hours
29980	mans0954 author:mans0954	refactor(RingTheory/Polynomial/Resultant/Quadratic): Re-implement QuadraticDiscriminant for R[X]	Re-implement `Algebra/QuadraticDiscriminant` for polynomials. [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/discriminants.20of.20low.20degree.20polynomials/with/538010519) --- - [ ] depends on: #29981 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict please-adopt	208/0	Mathlib.lean,Mathlib/RingTheory/Polynomial/Resultant/Quadratic.lean	2	4	['JovanGerb', 'github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	JovanGerb assignee:JovanGerb	142-51359 4 months ago	195-24313 195 days ago	41-47019 41 days
29387	mans0954 author:mans0954	feat(Analysis/LocallyConvex/WeakSpace): toWeakSpace_closedAbsConvexHull_eq	The closed absolutely convex hull taken in the weak topology coincides with the closed absolutely convex hull taken in the original topology. --- - [ ] depends on: #29378 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR t-analysis please-adopt	133/68	Mathlib/Analysis/Convex/Basic.lean,Mathlib/Analysis/LocallyConvex/AbsConvex.lean,Mathlib/Analysis/LocallyConvex/AbsConvexOpen.lean,Mathlib/Analysis/LocallyConvex/BalancedCoreHull.lean,Mathlib/Analysis/LocallyConvex/Basic.lean,Mathlib/Analysis/Normed/Module/Dual.lean	6	5	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	142-51340 4 months ago	unknown	unknown
29378	mans0954 author:mans0954	feat(Analysis/LocallyConvex/AbsConvex): Balanced and AbsConvex sets under linear maps	Provide `Balanced` and `AbsConvex` versions of `Convex.linear_image`, `Convex.linear_preimage` and the `is_linear` equivalents. --- - [ ] depends on: #29342 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-analysis please-adopt	133/68	Mathlib/Analysis/Convex/Basic.lean,Mathlib/Analysis/LocallyConvex/AbsConvex.lean,Mathlib/Analysis/LocallyConvex/AbsConvexOpen.lean,Mathlib/Analysis/LocallyConvex/BalancedCoreHull.lean,Mathlib/Analysis/LocallyConvex/Basic.lean,Mathlib/Analysis/Normed/Module/Dual.lean	6	4	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	142-51180 4 months ago	230-41081 230 days ago	0-14240 3 hours
12934	grunweg author:grunweg	chore: replace more uses of > or ≥ by < or ≤	These were flagged by the linter in https://github.com/leanprover-community/mathlib4/pull/12879: it is easy to simple avoid > or ≥ in hypotheses or haves. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author help-wanted	41/42	Archive/Imo/Imo1962Q1.lean,Archive/Imo/Imo1988Q6.lean,Archive/Imo/Imo1994Q1.lean,Archive/Imo/Imo2005Q3.lean,Archive/Imo/Imo2006Q3.lean,Archive/Imo/Imo2008Q2.lean,Archive/Imo/Imo2008Q3.lean,Archive/Imo/Imo2019Q4.lean,Archive/Sensitivity.lean,Archive/Wiedijk100Theorems/CubingACube.lean,Mathlib/Tactic/Linarith/Datatypes.lean,test/cancel_denoms.lean,test/congr.lean,test/interval_cases.lean,test/observe.lean	15	12	['YaelDillies', 'adomani', 'github-actions', 'grunweg', 'jcommelin', 'urkud']	nobody	141-38406 4 months ago	unknown	unknown
20719	gio256 author:gio256	feat(AlgebraicTopology): delaborators for truncated simplicial notations	We add delaborators for the following notations, introduced in #20688: - `⦋m⦌ₙ`, which denotes the `m`-dimensional simplex in the `n`-truncated simplex category. - `X _⦋m⦌ₙ`, which denotes the `m`-th term of an `n`-truncated simplicial object `X`. - `X ^⦋m⦌ₙ`, which denotes the `m`-th term of an `n`-truncated cosimplicial object `X`. If `pp.proofs` is set to `true`, we also pretty-print the proof `p : m ≤ n` for all three notations as `⦋m, p⦌ₙ`, `X _⦋m, p⦌ₙ`, and `X ^⦋m, p⦌ₙ`, respectively. Credit to @kmill for one piece of code and much metaprogramming inspiration. --- - [x] depends on: #20688 - [x] depends on: #23018 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebraic-topology infinity-cosmos t-meta please-adopt will-close-soon	525/33	Mathlib.lean,Mathlib/AlgebraicTopology/SimplexCategory/Basic.lean,Mathlib/AlgebraicTopology/SimplexCategory/Defs.lean,Mathlib/AlgebraicTopology/SimplicialObject/Basic.lean,Mathlib/Tactic.lean,Mathlib/Tactic/SimplexCategory.lean,Mathlib/Util/Superscript.lean,MathlibTest/SimplexCategory.lean,MathlibTest/SimplicialObject.lean,MathlibTest/superscript.lean,scripts/noshake.json	11	24	['eric-wieser', 'gio256', 'github-actions', 'joneugster', 'kim-em', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot']	nobody	137-1357 4 months ago	unknown	unknown
21476	grunweg author:grunweg	feat(lint-style): enable running on downstream projects	Enable lint-style to run on downstream projects, by making the following modifications: - allow passing an explicit list of libraries to lint: if nothing is passed, it lints `Mathlib`, `Archive` and `Counterexamples` (as before); otherwise, it lints precisely the passed modules - only check init imports, undocumented scripts and the errors from `lint-style.py` when linting Mathlib - make the style exceptions file configurable and optional: using the `nolints-file` flag, the exceptions file can be configured. If the flag is omitted, we try to find a file at `scripts/nolints-style.txt` --- and otherwise proceed with no style exceptions. This means mathlib can continue unchanged, and downstream projects can either add an explicit exceptions file, or proceed without any exceptions. After this PR, one should be able to run lint-style on a downstream project by `lake exe lint-style ProjectName`. Prompted by [this zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/lint-style.20for.20downstream.20libraries). --- - [x] depends on: #24570 - [x] depends on: #24953 (I did not test the last part.) [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-linter awaiting-author please-adopt	58/19	Mathlib/Tactic/Linter/TextBased.lean,scripts/lint-style.lean	2	21	['Vierkantor', 'adomani', 'github-actions', 'grunweg', 'joneugster', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot']	nobody	130-21092 4 months ago	unknown	unknown
8608	eric-wieser author:eric-wieser	feat: multiplicativize `AddTorsor`	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP t-algebra please-adopt label:t-algebra$	268/199	Mathlib/Algebra/AddTorsor.lean,Mathlib/Algebra/Group/Defs.lean,Mathlib/Data/Set/Pointwise/SMul.lean,Mathlib/Tactic/ToAdditive.lean	4	2	['alreadydone']	nobody	125-51951 4 months ago	unknown	unknown
23042	joneugster author:joneugster	feat(CategoryTheory/Enriched/Limits): add HasConicalLimitsOfSize.shrink	--- Note: I've marked this "WIP" because I'm not yet sure when this will be needed and I'd probably put the PR on the queue once I've created some follow-up needing it. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-category-theory infinity-cosmos please-adopt	22/1	Mathlib/CategoryTheory/Enriched/Limits/HasConicalLimits.lean	1	1	['github-actions']	nobody	107-41901 3 months ago	unknown	unknown
23142	joneugster author:joneugster	feat(CategoryTheory/Enriched/Limits): add API for HasConicalLimit	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-category-theory infinity-cosmos please-adopt	52/9	Mathlib/CategoryTheory/Enriched/Limits/HasConicalLimits.lean	1	2	['github-actions', 'joelriou']	nobody	107-41901 3 months ago	unknown	unknown
23145	joneugster author:joneugster	feat(CategoryTheory/Enriched/Limits): add IsConicalLimits	--- - [ ] depends on: #23142 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR t-category-theory infinity-cosmos please-adopt	221/9	Mathlib.lean,Mathlib/CategoryTheory/Enriched/Limits/HasConicalLimits.lean,Mathlib/CategoryTheory/Enriched/Limits/IsConicalLimit.lean	3	3	['github-actions', 'joelriou', 'mathlib4-dependent-issues-bot']	nobody	107-41900 3 months ago	unknown	unknown
35339	grunweg author:grunweg	feat: "confusing variables" linter	Continuation of #15400. This linter flags variable commands which both update an existing binder annotation and declare new variables: these can yield confusing or misleading error messages (see https://github.com/leanprover/lean4/issues/2789). Instead, these should be split in several variable statements. ------------ Help fixing these errors is welcome! Currently, the linter only catches some cases, when the updated binder is from a previous scope. To make it catch all cases, the linter could insert a section before the variable command and use that scope instead. See [zulip](https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Get.20scope.20before.20some.20syntax.20is.20evaluated) [discussions](https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Determining.20variable.20binders.20from.20syntax). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt merge-conflict awaiting-CI t-linter	220/9	Cache/Requests.lean,Mathlib/FieldTheory/AbelRuffini.lean,Mathlib/FieldTheory/IntermediateField/Basic.lean,Mathlib/FieldTheory/KummerExtension.lean,Mathlib/LinearAlgebra/CliffordAlgebra/Basic.lean,Mathlib/Tactic/Linter/Lint.lean,Mathlib/Tactic/Linter/Style.lean,MathlibTest/LintStyle.lean	8	0	[]	nobody	107-12271 3 months ago	unknown	unknown
35341	grunweg author:grunweg	feat: lint against the tactic.skipAssignedInstances option in mathlib	This means we can remove the corresponding technical debt entry. Re-created version of #20872. --- [This comment](https://github.com/leanprover-community/mathlib4/pull/20872#issuecomment-2602743770) might still be relevant: does this linter need adaptations to recursively parse the outer `set_option`s? Wasn't there code written semi-recently which did this? [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt t-linter merge-conflict	54/3	Mathlib/Tactic/Linter/Style.lean,MathlibTest/LintStyle.lean	2	3	['github-actions', 'mathlib-merge-conflicts']	nobody	106-68470 3 months ago	unknown	unknown
35545	joelriou author:joelriou	feat(Algebra/Category/ModuleCat): the internal hom for presheaves of modules	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra WIP please-adopt label:t-algebra$	141/0	Mathlib.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/InternalHom.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Pushforward.lean	3	1	['github-actions']	nobody	102-11279 3 months ago	unknown	unknown
8102	miguelmarco author:miguelmarco	feat(Tactic): add `unify_denoms` and `collect_signs` tactics	This PR adds four new tactics: - `unify_denoms` tries to put expressions with several divisions in a form with only one division. In the case of fields, it works similarly to `field_simp`, but if the hypothesis about denominators being nonzero are not present, it assumes them, and leaves them as new goals to prove. In that sense, it is an "unsafe" tactic (but can be useful nevertheless, for example when you can't find which exact hypothesis is missing). It also works with expressions of naturals and Euclidean domains, assuming the corresponding hypothesis about the denominators dividing the numerators. - `unify_denoms!` extends `unify_denoms` to work with (in)equalities, assuming also that the denominators, once in normal form, are positive. - `collect_signs` works similarly with expressions using sums and substractions: it tries to put them in a form of one sum minus other sum. In the case of working with naturals, it assumes that we never substract a bigger number from a smaller one. Both are implemented essentially as a macro that combines several rewriting rules. Some new lemmas with the corresponding rules are added. ---	please-adopt new-contributor merge-conflict modifies-tactic-syntax good first issue t-meta	407/0	Mathlib.lean,Mathlib/Algebra/EuclideanDomain/Basic.lean,Mathlib/Tactic.lean,Mathlib/Tactic/CollectSigns.lean,Mathlib/Tactic/UnifyDenoms.lean,MathlibTest/unify_denoms.lean,scripts/noshake.json	7	55	['Paul-Lez', 'YaelDillies', 'github-actions', 'joneugster', 'kbuzzard', 'mathlib4-merge-conflict-bot', 'miguelmarco']	nobody	95-3812 3 months ago	unknown	unknown
35193	Brian-Nugent author:Brian-Nugent	feat(Topology/Closeds): implement category of closed sets in topological spaces	I copied over the nice API for working with `TopologicalSpace.Opens` as a category over for `TopologicalSpace.Closeds`. The only thing that did not immediately transfer was `Topology.IsInducing.functorObj` so I omitted it. Based on work of @kim-em --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor please-adopt merge-conflict awaiting-author	385/0	Mathlib.lean,Mathlib/Topology/Category/TopCat/Closeds.lean,Mathlib/Topology/Category/TopCat/Opens.lean	2	24	['Brian-Nugent', 'dagurtomas', 'github-actions', 'mathlib-merge-conflicts']	dagurtomas assignee:dagurtomas	88-82482 2 months ago	73-82555 73 days ago	17-62518 17 days
34501	eric-wieser author:eric-wieser	chore(Data/Fintype/Induction): add a workaround for a bug in `induction`	This works around leanprover/lean4#4246, as Zulip threads frequently run up against this. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-meta please-adopt	15/1	Mathlib/Data/Fintype/Option.lean	1	3	['github-actions', 'joneugster']	joneugster assignee:joneugster	88-20009 2 months ago	unknown	unknown
22366	kim-em author:kim-em	feat: `check_equalities` tactic for diagnosing defeq problems	The `check_equalities` tactic, which checks the typing of equalities in the goal, reporting discrepancies between the implicit type argument of the equality, and the inferred types of the left and right hand sides, at "instances and reducible" transparency. Reports from this tactic do not necessarily indicate a problem, although typically `simp` should reduce rather than increase the reported discrepancies. `check_equalities` may be useful in diagnosing uses of `erw`.	t-meta please-adopt WIP	123/4	Mathlib.lean,Mathlib/Tactic.lean,Mathlib/Tactic/Basic.lean,Mathlib/Tactic/CategoryTheory/CheckCompositions.lean,Mathlib/Tactic/CheckEqualities.lean,Mathlib/Tactic/Common.lean,MathlibTest/check_equalities.lean	7	21	['adomani', 'b-mehta', 'eric-wieser', 'fpvandoorn', 'github-actions', 'grunweg', 'kim-em', 'mathlib-bors', 'mathlib4-merge-conflict-bot']	adamtopaz assignee:adamtopaz	84-50159 2 months ago	71-11616 71 days ago	16-84211 16 days
9605	davikrehalt author:davikrehalt	feat(Data/Finset & List): Add Lemmas for Sorting and Filtering	This PR includes several useful lemmas to the Data/Finset and Data/List modules in Lean's mathlib: 1. `toFinset_filter` (List): Shows that filtering commutes with toFinset. 2. `toFinset_is_singleton_implies_replicate` (List): Shows a list with a singleton toFinset is a List.replicate. 3. `filter_sort_commute` (Finset): Sorting and filtering can be interchanged in Finsets. 4. `Sorted.filter` (List): A sorted list stays sorted after filtering. 5. `Sorted.append_largest` (List): Appending the largest element keeps a list sorted. 6. `sort_monotone_map` (Finset): Relates sorting of a Finset after mapping to sorting of a list. 7. `sort_insert_largest` (Finset): Sorting a Finset with an inserted largest element. 8. `sort_range` (Finset): Sorting a range in a Finset equals the corresponding range list. 9. ~~`filter_eval_true` (List): Filtering a list with a predicate always true keeps the list unchanged.~~ 10. ~~`filter_eval_false` (List): Filtering with an always-false predicate gives an empty list.~~ 11. ~~`pairwise_concat` (List): Iff condition for Pairwise relation in concatenated lists (similar to pairwise_join).~~ 12. `list_map_toFinset` (Finset): toFinset commutes with map under injection --- - [x] depends on: #15952 This is my first PR to mathlib, so I'm not too familiar with etiquette's and more specifically there are two proofs in the PR which uses aesop, and I am not sure if it's frowned upon. I kept the aesop in there for now as I couldn't construct very short proofs otherwise. The sort_range function proof was suggested in https://leanprover.zulipchat.com/#narrow/stream/113489-new-members/topic/Computing.20Finset.20sort.20of.20Finset.20range/near/410346731 by Ruben Van de Velde. Thanks for your time for improving this PR.	please-adopt t-data new-contributor merge-conflict awaiting-author	71/0	Mathlib/Data/Finset/Basic.lean,Mathlib/Data/Finset/Image.lean,Mathlib/Data/Finset/Sort.lean,Mathlib/Data/List/Sort.lean	4	30	['YaelDillies', 'davikrehalt', 'eric-wieser', 'github-actions', 'jcommelin', 'urkud', 'vihdzp']	nobody	82-19279 2 months ago	unknown	unknown
29856	mans0954 author:mans0954	feat(Analysis/Normed/Ring/Basic): Add NonUnitalNonAssocSeminormedRing and NonUnitalNonAssocNormedRing	Adds the classes `NonUnitalNonAssocSeminormedRing` and `NonUnitalNonAssocNormedRing` and relaxes the `NonUnitalSeminormedRing` section to `NonUnitalNonAssocSeminormedRing`. Examples of non-unital non-associative normed rings include non-untial JB-algebras and non-unital JB*-algebras. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis please-adopt	110/11	Mathlib/Analysis/Normed/Ring/Basic.lean,MathlibTest/TCSynth.lean	2	15	['github-actions', 'j-loreaux', 'leanprover-bot']	ADedecker and j-loreaux assignee:j-loreaux assignee:ADedecker	81-41564 2 months ago	195-60751 195 days ago	57-16399 57 days
33466	Shreyas4991 author:Shreyas4991	refactor(Combinatorics/Digraph): add vertex sets	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics merge-conflict please-adopt	382/55	Mathlib/Combinatorics/Digraph/Basic.lean,Mathlib/Combinatorics/Digraph/Orientation.lean	2	83	['IvanRenison', 'Shreyas4991', 'SnirBroshi', 'YaelDillies', 'copilot-pull-request-reviewer', 'github-actions', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot', 'vihdzp', 'vlad902']	awainverse assignee:awainverse	81-31859 2 months ago	81-31859 81 days ago	27-54021 27 days
37730	RemyDegenne author:RemyDegenne	feat: define total variation distance	Define the total variation distance between two finite measures, using the variation of the difference seen as signed measures. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt WIP t-measure-probability	56/0	Mathlib.lean,Mathlib/InformationTheory/TotalVariation/Basic.lean	2	1	['github-actions']	nobody	56-22254 1 month ago	unknown	unknown
22925	ggranberry author:ggranberry	feat(Mathlib/PlaceHolder/ToeplitzHausdorff): Toeplitz-Hausdorff	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP new-contributor will-close-soon awaiting-author help-wanted t-analysis	411/0	Mathlib/PlaceHolder/ToeplitzHausdorff.lean,Mathlib/PlaceHolder/ToeplitzHausdorff_v2.lean	2	16	['AntoineChambert-Loir', 'faenuccio', 'ggranberry', 'github-actions', 'vihdzp']	faenuccio assignee:faenuccio	18-6623 18 days ago	unknown	unknown
26088	grunweg author:grunweg	chore(Linter/DirectoryDependency): move forbidden directories into a JSON file	This PR continues the work from #25406. Original PR: https://github.com/leanprover-community/mathlib4/pull/25406	please-adopt t-linter merge-conflict	387/19	Mathlib/Tactic/Linter/DirectoryDependency.lean,scripts/README.md,scripts/forbiddenDirs.json	3	7	['Vierkantor', 'github-actions', 'grunweg', 'mathlib4-merge-conflict-bot', 'rosborn']	nobody	15-81484 15 days ago	unknown	unknown
34440	grunweg author:grunweg	feat: linter for name components in uppercase	Per the naming convention, these are errors (unless they are an abbreviation). Mathlib has many violations at the moment: for this reason, we add this as an environment linter and automatically add all current exceptions. Once these have been fixed, converting to a syntax linter is desirable. Until then, track the number of such exceptions as technical debt. --- [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/naming.20convention.20linter/with/570617527) Note to self: wait for CI, then do a final nolints update. and try to implement the follow-up soon [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-linter large-import awaiting-author please-adopt merge-conflict	1024/8	Mathlib/Tactic/Linter/Style.lean,MathlibTest/DoubleUnderscore.lean,MathlibTest/Lint.lean,MathlibTest/LintStyle.lean,scripts/nolints.json	5	29	['Vierkantor', 'github-actions', 'grunweg', 'joneugster', 'mathlib-merge-conflicts']	nobody	11-19652 11 days ago	104-21533 104 days ago	13-63250 13 days
35344	grunweg author:grunweg	feat: lint upon uses of the mono tactic	suggesting to use `gcongr` instead. In general, `mono` is unmaintained, was only partially ported --- and gcongr at this point is more featureful, actively developed and has a nicer user interface. The topic was also discussed [on zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Porting.20note.3A.20Fixing.20up.20.60mono.60/with/445125798). --- TODO: update the linter wording, fix its implementation and wait until tests pass Rebased and migrated version of #25700. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt t-linter RFC merge-conflict	4/0	MathlibTest/DeprecatedSyntaxLinter.lean,MathlibTest/Monotonicity.lean	2	3	['github-actions', 'grunweg', 'mathlib-merge-conflicts']	nobody	7-39825 7 days ago	unknown	unknown

PRs with just a merge conflict

Number	Author	Title	Description	Labels	+/-	Modified files (first 100)	📝	💬	All users who commented or reviewed	Assignee(s)	Updated	Last status change	total time in review
24823	eric-wieser author:eric-wieser	refactor: add `hom` lemmas for the `MonoidalCategory` structure on `ModuleCat`	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebra label:t-algebra$	148/164	Mathlib/Algebra/Category/FGModuleCat/Basic.lean,Mathlib/Algebra/Category/ModuleCat/Adjunctions.lean,Mathlib/Algebra/Category/ModuleCat/Monoidal/Basic.lean,Mathlib/Algebra/Category/ModuleCat/Monoidal/Closed.lean,Mathlib/Algebra/Category/ModuleCat/Monoidal/Symmetric.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Free.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Generator.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Monoidal.lean,Mathlib/CategoryTheory/Monoidal/Internal/Module.lean,Mathlib/RepresentationTheory/Coinvariants.lean,Mathlib/RepresentationTheory/Rep.lean	11	21	['101damnations', 'YaelDillies', 'eric-wieser', 'github-actions', 'joelriou', 'kbuzzard', 'leanprover-community-bot-assistant']	101damnations assignee:101damnations	332-38646 10 months ago	332-38646 332 days ago	25-46777 25 days
25988	Multramate author:Multramate	refactor(AlgebraicGeometry/EllipticCurve/*): replace Fin 3 with products	This PR continues the work from #24593. Original PR: https://github.com/leanprover-community/mathlib4/pull/24593	merge-conflict t-algebraic-geometry	1000/1022	Mathlib/AlgebraicGeometry/EllipticCurve/Jacobian/Basic.lean,Mathlib/AlgebraicGeometry/EllipticCurve/Jacobian/Formula.lean,Mathlib/AlgebraicGeometry/EllipticCurve/Jacobian/Point.lean,Mathlib/AlgebraicGeometry/EllipticCurve/Projective/Basic.lean,Mathlib/AlgebraicGeometry/EllipticCurve/Projective/Formula.lean,Mathlib/AlgebraicGeometry/EllipticCurve/Projective/Point.lean	6	3	['Multramate', 'github-actions', 'leanprover-community-bot-assistant']	nobody	332-38088 10 months ago	unknown	unknown
26067	mapehe author:mapehe	feat(Topology/StoneCech): exists_continuous_surjection_from_StoneCech_to_dense_range	This lemma formalises the following version of the maximality property of the Stone–Čech compactification: If `f : α → β` is a continuous map from a topological space `α` to a Hausdorff space `β` with dense range, then there exists a continuous surjection from `StoneCech α` to `β` extending `f`. In particular, `StoneCech α` is the “largest” compact Hausdorff space into which `α` densely embeds, in the sense that any other such space is a continuous image of it. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-topology	18/0	Mathlib/Topology/StoneCech.lean	1	2	['github-actions', 'leanprover-community-bot-assistant']	nobody	329-19466 10 months ago	unknown	unknown
26200	adomani author:adomani	fix: add label when landrun fails	Adds the `permission-denied` label on PRs that get blocked by landrun. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict CI	68/8	.github/build.in.yml,.github/workflows/bors.yml,.github/workflows/build.yml,.github/workflows/build_fork.yml	4	2	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	300-54081 9 months ago	unknown	unknown
27451	kckennylau author:kckennylau	feat(RingTheory/Valuation): define ball, closed ball, and sphere	From the 2025 Local Class Field Theory Workshop. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory	27/0	Mathlib/RingTheory/Valuation/Basic.lean	1	13	['JovanGerb', 'github-actions', 'kckennylau', 'mathlib4-merge-conflict-bot', 'pechersky', 'wwylele']	nobody	295-184 9 months ago	unknown	unknown
27987	kckennylau author:kckennylau	feat(RingTheory/Valuation): define ball, closed ball, and sphere	--- The pullback PR of #26827 and #27451. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory large-import	73/0	Mathlib/RingTheory/Valuation/Basic.lean	1	4	['JovanGerb', 'github-actions', 'kckennylau', 'mathlib4-merge-conflict-bot']	nobody	294-86213 9 months ago	unknown	unknown
27003	eric-wieser author:eric-wieser	chore: use `Simp.ResultQ` more often	Also uses `~q` in place of manual `isDefEq` matching. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-meta	18/22	Mathlib/Tactic/NormNum/Core.lean,Mathlib/Tactic/NormNum/Result.lean,Mathlib/Tactic/ReduceModChar.lean	3	7	['JovanGerb', 'eric-wieser', 'github-actions', 'mathlib4-merge-conflict-bot']	JovanGerb assignee:JovanGerb	293-14437 9 months ago	293-14438 293 days ago	29-71942 29 days
28622	alreadydone author:alreadydone	chore(Mathlib): replace `=>` by `↦`	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	51792/51792	Mathlib/Algebra/AddTorsor/Basic.lean,Mathlib/Algebra/AddTorsor/Defs.lean,Mathlib/Algebra/Algebra/Basic.lean,Mathlib/Algebra/Algebra/Bilinear.lean,Mathlib/Algebra/Algebra/Defs.lean,Mathlib/Algebra/Algebra/Equiv.lean,Mathlib/Algebra/Algebra/Hom.lean,Mathlib/Algebra/Algebra/Hom/Rat.lean,Mathlib/Algebra/Algebra/NonUnitalHom.lean,Mathlib/Algebra/Algebra/NonUnitalSubalgebra.lean,Mathlib/Algebra/Algebra/Operations.lean,Mathlib/Algebra/Algebra/Opposite.lean,Mathlib/Algebra/Algebra/Prod.lean,Mathlib/Algebra/Algebra/Rat.lean,Mathlib/Algebra/Algebra/Spectrum/Basic.lean,Mathlib/Algebra/Algebra/Spectrum/Pi.lean,Mathlib/Algebra/Algebra/Spectrum/Quasispectrum.lean,Mathlib/Algebra/Algebra/Subalgebra/Basic.lean,Mathlib/Algebra/Algebra/Subalgebra/Centralizer.lean,Mathlib/Algebra/Algebra/Subalgebra/Directed.lean,Mathlib/Algebra/Algebra/Subalgebra/IsSimpleOrder.lean,Mathlib/Algebra/Algebra/Subalgebra/Lattice.lean,Mathlib/Algebra/Algebra/Subalgebra/Matrix.lean,Mathlib/Algebra/Algebra/Subalgebra/Operations.lean,Mathlib/Algebra/Algebra/Subalgebra/Pointwise.lean,Mathlib/Algebra/Algebra/Subalgebra/Prod.lean,Mathlib/Algebra/Algebra/Subalgebra/Unitization.lean,Mathlib/Algebra/Algebra/Tower.lean,Mathlib/Algebra/Algebra/TransferInstance.lean,Mathlib/Algebra/Algebra/Unitization.lean,Mathlib/Algebra/Algebra/ZMod.lean,Mathlib/Algebra/AlgebraicCard.lean,Mathlib/Algebra/BigOperators/Associated.lean,Mathlib/Algebra/BigOperators/Expect.lean,Mathlib/Algebra/BigOperators/Fin.lean,Mathlib/Algebra/BigOperators/Finprod.lean,Mathlib/Algebra/BigOperators/Finsupp/Basic.lean,Mathlib/Algebra/BigOperators/Finsupp/Fin.lean,Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean,Mathlib/Algebra/BigOperators/Group/Finset/Defs.lean,Mathlib/Algebra/BigOperators/Group/Finset/Piecewise.lean,Mathlib/Algebra/BigOperators/Group/Finset/Sigma.lean,Mathlib/Algebra/BigOperators/Group/List/Basic.lean,Mathlib/Algebra/BigOperators/Group/List/Defs.lean,Mathlib/Algebra/BigOperators/Group/List/Lemmas.lean,Mathlib/Algebra/BigOperators/Group/Multiset/Basic.lean,Mathlib/Algebra/BigOperators/Group/Multiset/Defs.lean,Mathlib/Algebra/BigOperators/GroupWithZero/Finset.lean,Mathlib/Algebra/BigOperators/Intervals.lean,Mathlib/Algebra/BigOperators/Option.lean,Mathlib/Algebra/BigOperators/Pi.lean,Mathlib/Algebra/BigOperators/Ring/Finset.lean,Mathlib/Algebra/BigOperators/Ring/Multiset.lean,Mathlib/Algebra/Category/AlgCat/Basic.lean,Mathlib/Algebra/Category/AlgCat/Limits.lean,Mathlib/Algebra/Category/AlgCat/Monoidal.lean,Mathlib/Algebra/Category/BialgCat/Basic.lean,Mathlib/Algebra/Category/BoolRing.lean,Mathlib/Algebra/Category/CoalgCat/Basic.lean,Mathlib/Algebra/Category/CoalgCat/ComonEquivalence.lean,Mathlib/Algebra/Category/FGModuleCat/Limits.lean,Mathlib/Algebra/Category/Grp/AB.lean,Mathlib/Algebra/Category/Grp/Adjunctions.lean,Mathlib/Algebra/Category/Grp/Basic.lean,Mathlib/Algebra/Category/Grp/Biproducts.lean,Mathlib/Algebra/Category/Grp/CartesianMonoidal.lean,Mathlib/Algebra/Category/Grp/Colimits.lean,Mathlib/Algebra/Category/Grp/EpiMono.lean,Mathlib/Algebra/Category/Grp/FilteredColimits.lean,Mathlib/Algebra/Category/Grp/Images.lean,Mathlib/Algebra/Category/Grp/Kernels.lean,Mathlib/Algebra/Category/Grp/LargeColimits.lean,Mathlib/Algebra/Category/Grp/LeftExactFunctor.lean,Mathlib/Algebra/Category/Grp/Limits.lean,Mathlib/Algebra/Category/Grp/Preadditive.lean,Mathlib/Algebra/Category/Grp/ZModuleEquivalence.lean,Mathlib/Algebra/Category/Grp/Zero.lean,Mathlib/Algebra/Category/GrpWithZero.lean,Mathlib/Algebra/Category/HopfAlgCat/Basic.lean,Mathlib/Algebra/Category/ModuleCat/Adjunctions.lean,Mathlib/Algebra/Category/ModuleCat/Basic.lean,Mathlib/Algebra/Category/ModuleCat/Biproducts.lean,Mathlib/Algebra/Category/ModuleCat/ChangeOfRings.lean,Mathlib/Algebra/Category/ModuleCat/Colimits.lean,Mathlib/Algebra/Category/ModuleCat/EpiMono.lean,Mathlib/Algebra/Category/ModuleCat/FilteredColimits.lean,Mathlib/Algebra/Category/ModuleCat/Images.lean,Mathlib/Algebra/Category/ModuleCat/Injective.lean,Mathlib/Algebra/Category/ModuleCat/Kernels.lean,Mathlib/Algebra/Category/ModuleCat/Limits.lean,Mathlib/Algebra/Category/ModuleCat/Monoidal/Basic.lean,Mathlib/Algebra/Category/ModuleCat/Monoidal/Closed.lean,Mathlib/Algebra/Category/ModuleCat/Monoidal/Symmetric.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Abelian.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Colimits.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Limits.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Pushforward.lean,Mathlib/Algebra/Category/ModuleCat/Presheaf/Sheafify.lean,Mathlib/Algebra/Category/ModuleCat/Products.lean	3838	4	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	286-59113 9 months ago	286-59114 286 days ago	0-61040 16 hours
28626	alreadydone author:alreadydone	chore(Archive, Counterexamples): replace => by ↦	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	288/288	Archive/Arithcc.lean,Archive/Examples/IfNormalization/Result.lean,Archive/Examples/IfNormalization/WithoutAesop.lean,Archive/Examples/PropEncodable.lean,Archive/Imo/Imo1959Q1.lean,Archive/Imo/Imo1960Q1.lean,Archive/Imo/Imo1962Q4.lean,Archive/Imo/Imo1972Q5.lean,Archive/Imo/Imo1977Q6.lean,Archive/Imo/Imo1981Q3.lean,Archive/Imo/Imo1987Q1.lean,Archive/Imo/Imo1988Q6.lean,Archive/Imo/Imo1994Q1.lean,Archive/Imo/Imo1998Q2.lean,Archive/Imo/Imo2001Q2.lean,Archive/Imo/Imo2006Q3.lean,Archive/Imo/Imo2006Q5.lean,Archive/Imo/Imo2008Q2.lean,Archive/Imo/Imo2008Q4.lean,Archive/Imo/Imo2011Q3.lean,Archive/Imo/Imo2013Q1.lean,Archive/Imo/Imo2019Q1.lean,Archive/Imo/Imo2024Q5.lean,Archive/MiuLanguage/Basic.lean,Archive/MiuLanguage/DecisionSuf.lean,Archive/OxfordInvariants/Summer2021/Week3P1.lean,Archive/Sensitivity.lean,Archive/Wiedijk100Theorems/AbelRuffini.lean,Archive/Wiedijk100Theorems/AreaOfACircle.lean,Archive/Wiedijk100Theorems/AscendingDescendingSequences.lean,Archive/Wiedijk100Theorems/BallotProblem.lean,Archive/Wiedijk100Theorems/BirthdayProblem.lean,Archive/Wiedijk100Theorems/BuffonsNeedle.lean,Archive/Wiedijk100Theorems/CubingACube.lean,Archive/Wiedijk100Theorems/FriendshipGraphs.lean,Archive/Wiedijk100Theorems/Konigsberg.lean,Archive/Wiedijk100Theorems/Partition.lean,Archive/Wiedijk100Theorems/SumOfPrimeReciprocalsDiverges.lean,Archive/ZagierTwoSquares.lean,Counterexamples/AharoniKorman.lean,Counterexamples/CanonicallyOrderedCommSemiringTwoMul.lean,Counterexamples/CharPZeroNeCharZero.lean,Counterexamples/CliffordAlgebraNotInjective.lean,Counterexamples/DirectSumIsInternal.lean,Counterexamples/GameMultiplication.lean,Counterexamples/Girard.lean,Counterexamples/HomogeneousPrimeNotPrime.lean,Counterexamples/MapFloor.lean,Counterexamples/MonicNonRegular.lean,Counterexamples/Phillips.lean,Counterexamples/Pseudoelement.lean,Counterexamples/QuadraticForm.lean,Counterexamples/SorgenfreyLine.lean,Counterexamples/ZeroDivisorsInAddMonoidAlgebras.lean	54	2	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	285-1839 9 months ago	285-1840 285 days ago	2-46961 2 days
27403	MoritzBeroRoos author:MoritzBeroRoos	fix: replace probably erroneous usage of ⬝ (with old \cdot) by · (with \centerdot)	Discussion at [zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/.5Ccdot.20!.3D.20.5Ccenterdot). Currently the abbreviations \cdot and \centerdot resolve to different, with the naked eye nearly undistinguishable symbols (despite the c in cdot surely standing for center..). This pr replaces instances of ⬝ where · was probably meant. All of the replacement is in comments, except for the file bench_summary.lean which is used for priting the github benchmark results. Since this file is about scientific notation of numbers, sure · was meant to be used, not a rectangle. [Related](https://github.com/leanprover-community/mathlib4/pull/27399) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict new-contributor	195/195	Mathlib/Algebra/ContinuedFractions/Computation/Approximations.lean,Mathlib/Algebra/DirectSum/Idempotents.lean,Mathlib/Algebra/Lie/Derivation/Basic.lean,Mathlib/Algebra/Module/Equiv/Basic.lean,Mathlib/AlgebraicGeometry/EllipticCurve/DivisionPolynomial/Basic.lean,Mathlib/Analysis/Analytic/Constructions.lean,Mathlib/Analysis/CStarAlgebra/CStarMatrix.lean,Mathlib/Analysis/Calculus/ContDiff/Basic.lean,Mathlib/Analysis/Calculus/ContDiff/Bounds.lean,Mathlib/Analysis/Calculus/FDeriv/Symmetric.lean,Mathlib/Analysis/Fourier/FourierTransformDeriv.lean,Mathlib/Analysis/InnerProductSpace/Dual.lean,Mathlib/Analysis/InnerProductSpace/PiL2.lean,Mathlib/Analysis/Normed/Unbundled/InvariantExtension.lean,Mathlib/Analysis/SpecialFunctions/Complex/CircleAddChar.lean,Mathlib/Combinatorics/Configuration.lean,Mathlib/Combinatorics/SimpleGraph/AdjMatrix.lean,Mathlib/Combinatorics/SimpleGraph/LapMatrix.lean,Mathlib/Data/Matrix/Block.lean,Mathlib/Data/Matrix/ConjTranspose.lean,Mathlib/Data/Matrix/Hadamard.lean,Mathlib/Data/Matrix/Mul.lean,Mathlib/Data/Matrix/Notation.lean,Mathlib/Data/Matrix/Reflection.lean,Mathlib/Data/Matrix/RowCol.lean,Mathlib/Data/Matrix/Vec.lean,Mathlib/FieldTheory/PurelyInseparable/PerfectClosure.lean,Mathlib/Geometry/Manifold/GroupLieAlgebra.lean,Mathlib/GroupTheory/Coxeter/Matrix.lean,Mathlib/LinearAlgebra/CrossProduct.lean,Mathlib/LinearAlgebra/Matrix/BilinearForm.lean,Mathlib/LinearAlgebra/Matrix/DotProduct.lean,Mathlib/LinearAlgebra/Matrix/Nondegenerate.lean,Mathlib/LinearAlgebra/Matrix/Orthogonal.lean,Mathlib/LinearAlgebra/Matrix/PosDef.lean,Mathlib/LinearAlgebra/Matrix/SchurComplement.lean,Mathlib/LinearAlgebra/Matrix/SesquilinearForm.lean,Mathlib/LinearAlgebra/Matrix/Trace.lean,Mathlib/LinearAlgebra/Multilinear/Basic.lean,Mathlib/LinearAlgebra/PerfectPairing/Matrix.lean,Mathlib/LinearAlgebra/Projectivization/Constructions.lean,Mathlib/NumberTheory/NumberField/ProductFormula.lean,Mathlib/NumberTheory/SiegelsLemma.lean,Mathlib/RingTheory/DividedPowers/SubDPIdeal.lean,Mathlib/SetTheory/Ordinal/Veblen.lean,Mathlib/Topology/Algebra/Module/Equiv.lean,Mathlib/Topology/Homeomorph/Lemmas.lean,Mathlib/Topology/Instances/Matrix.lean,scripts/bench_summary.lean	49	5	['eric-wieser', 'github-actions', 'grunweg', 'leanprover-community-bot-assistant']	nobody	283-34875 9 months ago	306-10797 306 days ago	7-54020 7 days
28042	kckennylau author:kckennylau	feat(Topology/ValuativeRel): a topological basis indexed by pairs of elements	--- The pullback PR of #27314 and #27163. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory	140/23	Mathlib/RingTheory/Valuation/ValuativeRel.lean,Mathlib/Topology/Algebra/Valued/ValuativeRel.lean	2	3	['github-actions', 'grunweg', 'mathlib4-merge-conflict-bot']	nobody	283-34829 9 months ago	292-86273 292 days ago	7-4943 7 days
27399	MoritzBeroRoos author:MoritzBeroRoos	chore: replace every usage of ⬝ᵥ (with old \cdot) by ·ᵥ (with \centerdot)	Discussion at [zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/.5Ccdot.20!.3D.20.5Ccenterdot). Currently the abbreviations `\cdot` and `\centerdot` resolve to different, with the naked eye nearly undistinguishable symbols (despite the c in cdot surely standing for `center`..): - `\cdot` gives ⬝ [U+2B1D](https://www.compart.com/en/unicode/U+2B1D) "Black Very Small Square" - `\centerdot` gives · [U+00B7](https://www.compart.com/en/unicode/U+00B7) "Middle Dot" Mathlib mostly uses the `\centerdot` variant, except for the dotProduct notation and some probably unsuspecting people wanting \centerdot but getting \cdot in their comments and 6 uses of a notation using the raw `\cdot` without any subscript at `Mathlib\Topology\Homotopy\Product.lean`. This PR replaces the dot product `⬝ᵥ` with its `\centerdot` counterpart `·ᵥ`. The related PR [here](https://github.com/leanprover/vscode-lean4/pull/639) can then overwrite the `\cdot` abbreviation, to produce the same symbol as the `centerdot` abbreviation does. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict new-contributor	133/133	Mathlib/Analysis/CStarAlgebra/CStarMatrix.lean,Mathlib/Analysis/InnerProductSpace/PiL2.lean,Mathlib/Combinatorics/Configuration.lean,Mathlib/Combinatorics/SimpleGraph/AdjMatrix.lean,Mathlib/Combinatorics/SimpleGraph/LapMatrix.lean,Mathlib/Data/Matrix/Block.lean,Mathlib/Data/Matrix/ConjTranspose.lean,Mathlib/Data/Matrix/Hadamard.lean,Mathlib/Data/Matrix/Mul.lean,Mathlib/Data/Matrix/Notation.lean,Mathlib/Data/Matrix/Reflection.lean,Mathlib/Data/Matrix/RowCol.lean,Mathlib/Data/Matrix/Vec.lean,Mathlib/LinearAlgebra/CrossProduct.lean,Mathlib/LinearAlgebra/Matrix/BilinearForm.lean,Mathlib/LinearAlgebra/Matrix/DotProduct.lean,Mathlib/LinearAlgebra/Matrix/Nondegenerate.lean,Mathlib/LinearAlgebra/Matrix/Orthogonal.lean,Mathlib/LinearAlgebra/Matrix/PosDef.lean,Mathlib/LinearAlgebra/Matrix/SchurComplement.lean,Mathlib/LinearAlgebra/Matrix/SesquilinearForm.lean,Mathlib/LinearAlgebra/Matrix/Trace.lean,Mathlib/LinearAlgebra/PerfectPairing/Matrix.lean,Mathlib/LinearAlgebra/Projectivization/Constructions.lean,Mathlib/Topology/Instances/Matrix.lean	25	6	['MoritzBeroRoos', 'eric-wieser', 'github-actions', 'leanprover-community-bot-assistant']	nobody	282-83107 9 months ago	306-10798 306 days ago	7-54958 7 days
28148	kckennylau author:kckennylau	feat(Matrix): Simproc and Rw-proc for Matrix Transpose	Co-authored by Aaron Liu. ```lean example : !![1, 2, 3; 4, 5, 6]ᵀ = !![1, 4; 2, 5; 3, 6] := by rw [transpose_of% 2 3] example : !![1, 2, 3; 4, 5, 6]ᵀ = !![1, 4; 2, 5; 3, 6] := by rw [transpose_of] example : !![1, 2, 3; 4, 5, 6]ᵀ = !![1, 4; 2, 5; 3, 6] := by simp only [matrix_transpose] ``` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-meta	267/8	Mathlib.lean,Mathlib/Data/Matrix/Notation.lean,Mathlib/LinearAlgebra/UnitaryGroup.lean,Mathlib/Tactic.lean,Mathlib/Tactic/Simproc/Matrix.lean,MathlibTest/Simproc/Matrix.lean,MathlibTest/matrix.lean,scripts/noshake.json	8	32	['eric-wieser', 'github-actions', 'kckennylau', 'mathlib4-merge-conflict-bot', 'plp127']	eric-wieser assignee:eric-wieser	278-40041 9 months ago	278-40042 278 days ago	12-73277 12 days
26908	robin-carlier author:robin-carlier	feat(CategoryTheory/Monoidal/DayConvolution): alternative ext principle for unitors	Currently, our infrastructure for left/right unitors for Day convolution of functors `C ⥤ V` do not have satisfactory extensionality principle: the current way to characterize morphisms out of `U ⊛ F` is the default extensionality principle for Day convolution, which characterizes first such functors via functors out of `U ⊠ F`. Left unitors are then obtained using the fact `U ⊠ F` is a left Kan extension of a functor from `PUnit × C` (which is equivalent to `C`) but we did not record on its own this principle. Using the transitivity of left Kan extensions proved in #26899, we directly exhibit `U ⊛ F` as a left Kan extension of `F ⋙ tensorLeft (𝟙_ V)` along `tensorLeft (𝟙_ C)`. The unit of this Kan extension is composed exactly of the morphisms that appear in the [characterization of left unitors](https://leanprover-community.github.io/mathlib4_docs/Mathlib/CategoryTheory/Monoidal/DayConvolution.html#CategoryTheory.MonoidalCategory.DayConvolutionUnit.leftUnitor_hom_unit_app). We also slightly generalize the instances that express that external products with unitors are left Kan extensions, so that they can be used when taking external products with more complicated functors than currently. This is again useful when chaining extensionality lemmas for morphisms out of terms of the form `(F ⊛ U) ⊛ G`. We prove a similar thing for right unitors With this, it should be possible to have a much more satisfactory way of working with Day convolutions: this allows to "elimiinate" units without ending up with terms in an external product. --- - [ ] depends on: #26899 - [ ] depends on: #26906 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory	307/18	Mathlib/CategoryTheory/Functor/KanExtension/Basic.lean,Mathlib/CategoryTheory/Monoidal/DayConvolution.lean	2	4	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	266-86387 8 months ago	266-86388 266 days ago	0-219 3 minutes
27150	robin-carlier author:robin-carlier	feat(CategoryTheory/Monoidal/DayConvolution): constructors for braided and symmetric structure on day convolutions monoidal categories	Following the pattern in #27119, we give API to construct `BraidedCategory` and `SymmetricCategory` structures on a monoidal category equipped with a `LawfulDayConvolutionMonoidalCategoryStruct`. To achieve this, we introduce an other type class `LawfulDayConvolutionBraidedCategoryStruct` that bundles an associator isomorphism that behaves like the one constructed for functors in #27067. We provide a noncomputable constructor for this typeclass that takes as input fullness of the "realization" functor to a category of functors, and we show that the typeclasses are sufficient to define the desired structures. --- - [x] depends on: #27067 - [x] depends on: #26820 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory	826/9	Mathlib/CategoryTheory/Monoidal/DayConvolution.lean,Mathlib/CategoryTheory/Monoidal/DayConvolution/Braided.lean	2	5	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	266-81426 8 months ago	322-24721 322 days ago	0-407 6 minutes
27119	robin-carlier author:robin-carlier	feat(CategoryTheory/Monoidal/DayConvolution): constructors for closed monoidal day convolution monoidal structures	Following the pattern introduced in #26798 and #26820 and using results of #26879, we introduce a typeclass `LawfulDayConvolutionClosedMonoidalCategoryStruct` that encodes the data needed on a `LawfulDayConvolutionMonoidalCategoryStruct` to define well-behaved internal homs. We give a constructor assuming existence of relevant ends, and prove that this data defines a `MonoidalClosed` instance on the monoidal category structures one can deduce from `LawfulDayConvolutionMonoidalCategoryStruct`. --- - [x] depends on: #27079 - [x] depends on: #27091 - [x] depends on: #26879 - [x] depends on: #26820 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory	900/9	Mathlib/CategoryTheory/Monoidal/DayConvolution.lean,Mathlib/CategoryTheory/Monoidal/DayConvolution/Closed.lean	2	6	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	266-8877 8 months ago	unknown	unknown
28623	gilesgshaw author:gilesgshaw	feat(Logic/Basic): minor additions and simplification of proofs	Add new theorems and simplify proofs. Specifically, we add the family of related theorems `apply_dite_iff_exists`, `apply_dite_iff_forall`, `apply_ite_iff_and` and `apply_ite_iff_or`. For each other 'family' of theorems in the file that is analogous to the above, we do the following - Simplify proofs where possible, e.g. by appealing to the new theorems - Complete the family, if any of the corresponding four are missing - Rename to ensure consistency with the above pattern ---	merge-conflict t-logic new-contributor	83/55	Archive/Examples/IfNormalization/Result.lean,Archive/Examples/IfNormalization/WithoutAesop.lean,Mathlib/Algebra/ContinuedFractions/Computation/Translations.lean,Mathlib/Algebra/MvPolynomial/Variables.lean,Mathlib/Algebra/Notation/Indicator.lean,Mathlib/LinearAlgebra/Matrix/Rank.lean,Mathlib/Logic/Basic.lean,Mathlib/MeasureTheory/Measure/WithDensity.lean,Mathlib/SetTheory/Ordinal/Notation.lean	9	12	['eric-wieser', 'gilesgshaw', 'github-actions', 'mathlib4-merge-conflict-bot', 'plp127']	awainverse assignee:awainverse	266-2738 8 months ago	266-2739 266 days ago	10-52803 10 days
26154	ADedecker author:ADedecker	refactor: add refactored APIs for algebraic filter bases	This PR continues the work from #18437. Original PR: https://github.com/leanprover-community/mathlib4/pull/18437	merge-conflict t-topology	651/0	Mathlib.lean,Mathlib/Topology/Algebra/FilterBasis.lean,Mathlib/Topology/Algebra/FilterBasisNew.lean,Mathlib/Topology/Algebra/Nonarchimedean/Bases.lean,Mathlib/Topology/Algebra/Nonarchimedean/BasesNew.lean	5	3	['ADedecker', 'github-actions', 'mathlib4-merge-conflict-bot']	PatrickMassot assignee:PatrickMassot	260-14982 8 months ago	unknown	unknown
29330	plp127 author:plp127	chore: define `Fin.cycleIcc` with conditions	Redefine `Fin.cycleIcc` using conditionals instead of composing existing `Fin` operations together. Its worst-case runtime drops from O(n) to O(1). As a bonus, the definition no longer needs explaining. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-group-theory	61/68	Mathlib/GroupTheory/Perm/Fin.lean	1	10	['JovanGerb', 'eric-wieser', 'github-actions', 'mathlib4-merge-conflict-bot', 'plp127', 'tb65536']	nobody	251-26579 8 months ago	251-26580 251 days ago	19-76959 19 days
27214	robin-carlier author:robin-carlier	feat(CategoryTheory/Limits/Shapes/Pullback/Categorical): Categorical pullback squares	In this PR, we give the definition and first basic properties of categorical pullback squares. Using our previous work on `CategoricalPullback`, we define a typeclass `CatPullbackSquare T L R B` that asserts that a given `CatCommSq T L R B` is a "pullback square": this is the data of a chosen adjoint equivalence to the canonical functor from the top left corner of the square to the categorical pulback of its leg. Using this equivalence, be derive a universal property for functors from `X`with values in the top left corner of the square: they are equivalent to `CatCommSqOver R B X`, the category of categorical commutative squares over the cospan `R, B` with top left corner `X`. We prove some coherence result for this equivalence, most notably an isomorphism that, given `S : CatCommSqOver R B X`, bundles the two commutative triangles formed by the induced functor, and the coherence between the squares that these isomorphisms satisfy: this is conveniently bundled in the data of a single isomorphisms of `CatCommSqOver R B X`. Finally, we provide a `Prop`-class `IsCatPullbackSquare` that merely asserts the existence (via `Nonempty`) of the relevant data: we show that it is tautotogically equivalent to the propopsition that the canonical functor to the categorical pullback is an equivalence. --- - [ ] depends on: #26679 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory	786/1	Mathlib.lean,Mathlib/CategoryTheory/Limits/Shapes/Pullback/Categorical/Basic.lean,Mathlib/CategoryTheory/Limits/Shapes/Pullback/Categorical/Square.lean	3	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	245-78171 8 months ago	245-78172 245 days ago	0-4044 1 hour
26466	robin-carlier author:robin-carlier	feat(AlgebraicTopology/SimplexCategory/Augmented): the canonical monoid object in the augmented simplex category	Show that in the augmented simplex category, `⦋0⦌` is an internal monoid object. Future work will show that this is in fact the universal monoid object: for any monoidal category `C`, evaluation at `⦋0⦌` induces an equivalence of categories between `Mon_ C` and the category of monoidal functors from `AugmentedSimplexCategory` to `C`. The resulting augmented cosimplicial object one gets from this construction is sometimes called the "monoidal bar construction" attached to a monoid. This PR was split from #25743. --- - [ ] depends on: #25743 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebraic-topology t-category-theory	571/111	Mathlib.lean,Mathlib/AlgebraicTopology/SimplexCategory/Augmented.lean,Mathlib/AlgebraicTopology/SimplexCategory/Augmented/Basic.lean,Mathlib/AlgebraicTopology/SimplexCategory/Augmented/Mon_.lean,Mathlib/AlgebraicTopology/SimplexCategory/Augmented/Monoidal.lean,Mathlib/AlgebraicTopology/SimplexCategory/Basic.lean	6	4	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	245-11173 8 months ago	340-18457 340 days ago	0-1614 26 minutes
26578	robin-carlier author:robin-carlier	feat(CategoryTheory/Limits/Pullbacks/Categorical/CatCospanTransform): adjunctions of categorical cospans	We build upon the bicategory-like structure developed in #26447 and #26412 to define the notion of adjunctions of categorical cospans. This is a structure encoding the data of two `CatCospanTransform`s, along with the usual unit and counit morphisms as part of the data, satisfying the usual left and right triangle identities. We provide basic API for these, such as extracting adjunctions between individual components. We also provide a proof that the notion satisfies a "coherence": with our chosen constructor, the forward direction of the structure `CatCommSq` on the left adjoints correspond to the inverse of the square for the right adjoints through `mateEquiv`. These adjunctions will be used as a substrate for defining equivalences of categorical cospans in a future PR: such an equivalence will be a structure extending a `CatCospanAdjunction` with isomorphisms data on the unit and co-unit (we will however provide alternative constructors in sync with the constructor for equivalences of categories). --- - [x] depends on: #26447 - [x] depends on: #26547 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory large-import	205/0	Mathlib/CategoryTheory/Limits/Shapes/Pullback/Categorical/CatCospanTransform.lean	1	5	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	244-14398 8 months ago	unknown	unknown
27990	kckennylau author:kckennylau	feat(Counterexamples): a nontrivial valuation with discrete topology	This file constructs a valuation on `K[X]` satisfying `IsValuativeTopology K[X] ∧ Nonempty (valuation K[X]).RankOne ∧ IsNontrivial K[X] ∧ DiscreteTopology K[X]`, and proves that `IsValuativeTopology F ∧ IsNontrivial F ∧ DiscreteTopology F` is not possible if `F` is a field. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory	172/0	Counterexamples.lean,Counterexamples/DiscreteTopologyWithNontrivialValuation.lean	2	14	['github-actions', 'grunweg', 'kckennylau', 'mathlib4-merge-conflict-bot', 'pechersky']	nobody	232-84644 7 months ago	232-84645 232 days ago	67-78029 67 days
28132	dupuisf author:dupuisf	feat: preliminary `grind` tags for `IsUnit`	This PR adds preliminary `grind` tags for the `IsUnit` predicate. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebra label:t-algebra$	61/17	Mathlib/Algebra/Group/Action/Units.lean,Mathlib/Algebra/Group/Units/Defs.lean,Mathlib/Algebra/GroupWithZero/Units/Basic.lean,Mathlib/Algebra/Ring/Units.lean,Mathlib/Analysis/CStarAlgebra/ContinuousFunctionalCalculus/Order.lean,Mathlib/Analysis/SpecialFunctions/ContinuousFunctionalCalculus/Rpow/Basic.lean	6	3	['github-actions', 'mathlib4-merge-conflict-bot']	kim-em assignee:kim-em	209-61242 6 months ago	209-61243 209 days ago	80-71574 80 days
26827	pechersky author:pechersky	feat(Analysis/Normed/ValuativeRel): helper instance for NormedField	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) - [x] depends on: #26713 - [x] depends on: #26826	merge-conflict t-algebra t-number-theory t-analysis label:t-algebra$	211/27	Mathlib.lean,Mathlib/Analysis/Normed/ValuativeRel.lean,Mathlib/Topology/Algebra/Valued/ValuativeRel.lean	3	34	['ADedecker', 'adamtopaz', 'erdOne', 'github-actions', 'kbuzzard', 'kckennylau', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'pechersky']	kbuzzard assignee:kbuzzard	202-3446 6 months ago	202-3446 202 days ago	121-84082 121 days
24850	pechersky author:pechersky	feat(Topology/UniformSpace/Ultra): uniform spaces induced by pseudometrics are ultra if system is ultra	Any uniform space has a natural system of pseudometrics definable on it, comprised of those pseudometrics constructed from a descending chain of equivalence relation entourages. In a nonarchimedean uniformity, this pseudometric system induces the uniformity. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) - [x] depends on: #23111	merge-conflict t-topology	509/1	Mathlib.lean,Mathlib/Topology/MetricSpace/BundledFun.lean,Mathlib/Topology/UniformSpace/Ultra/Pseudometrizable.lean	3	9	['ADedecker', 'fpvandoorn', 'github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'pechersky']	urkud assignee:urkud	195-25933 6 months ago	195-25934 195 days ago	162-11470 162 days
26914	quangvdao author:quangvdao	feat(Data/PFunctor/Univariate): more definitions for univariate `PFunctor`	This PR defines several basic definitions of `PFunctor`, including zero, one, constants, monomials, coproduct (sum), product, sigma, pi, tensor product, universe lifting, and equivalence. We also add: (1) simple lemmas connecting the basic definitions, (2) an automatically derived ext lemma for `PFunctor` via `@[ext]` attribute Some things I'm not clear on: - I define `HAdd` and `HMul` instances for coproduct and product of poly functors having different universe levels. Should I also define `Add` and `Mul` instances for poly functors having the same universe level? - Is it ok to define notation for tensor product, i.e. `@[inherit_doc] scoped infixr:80 " ⊗ " => tensor`? I'm worried it might clash with other notation. - Need a double-check on the priority of notation. Some future definitions to add: - Various equivalences arising from arithmetic identities, e.g., `P + 0 ≃ₚ P`. - Definitions of Lenses and Charts (each of them will be a file or even a folder) - Exponential objects (corresponding to both `prod` and `tensor`) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-data	144/5	Mathlib/Data/PFunctor/Univariate/Basic.lean	1	20	['alexkeizer', 'eric-wieser', 'github-actions', 'mathlib4-merge-conflict-bot', 'quangvdao']	eric-wieser assignee:eric-wieser	195-25411 6 months ago	195-25412 195 days ago	133-23633 133 days
28125	nonisomorphiclinearmap author:nonisomorphiclinearmap	feat(Combinatorics): basic definition of simplicial complexes	This PR introduces the basic definition of a finite (abstract) simplicial complex, located in Mathlib/Combinatorics/SimplicialComplex/Basic.lean. --- This is our first contribution to mathlib. This work was done as part of the Fields Institute Summer Undergraduate Program on formalization in topological combinatorics. Eventually, we aim to formalize Lovasz's proof of the Kneser Conjecture and this is a small stepping stone in that direction. Some other commits will shortly depend on this one. We would like to acknowledge the Fields Institute for Research in Mathematical Sciences for their sponsorship. We would also like to thank our supervisors, Professor Chris Kapulkin and Mr. Daniel Carranza, for their guidance and support throughout this project. We would also like to thank our group members Tom Lindquist and Quang Minh Nguyen for our fruitful discussions.	merge-conflict t-combinatorics new-contributor	374/0	Mathlib.lean,Mathlib/Combinatorics/SimplicialComplex/Basic.lean,Mathlib/Combinatorics/SimplicialComplex/Category.lean,Mathlib/Combinatorics/SimplicialComplex/FacePoset.lean,Mathlib/Combinatorics/SimplicialComplex/Hom.lean	5	2	['github-actions', 'mathlib4-merge-conflict-bot']	awainverse assignee:awainverse	195-25106 6 months ago	195-25107 195 days ago	99-49043 99 days
28871	JaafarTanoukhi author:JaafarTanoukhi	feat(Combinatorics/Digraph): Tournaments	Define orientations and tournaments. Related to #26771. Co-authored-by: Rida Hamadani --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-combinatorics new-contributor	62/0	Mathlib.lean,Mathlib/Combinatorics/Digraph/Orientation.lean,Mathlib/Combinatorics/Digraph/Tournament.lean	3	6	['JaafarTanoukhi', 'Rida-Hamadani', 'SnirBroshi', 'github-actions', 'mathlib4-merge-conflict-bot']	kmill assignee:kmill	195-24953 6 months ago	195-24954 195 days ago	55-54848 55 days
29526	llllvvuu author:llllvvuu	feat: `Multiset.map f` identifies `f` up to permutation	Motivation: Reason about `Fintype`-indexed families via `Multiset` equality. Example use case 1: ```lean theorem Matrix.IsHermitian.cfc_eigenvalues {d : Type} [Fintype d] [DecidableEq d] {M : Matrix d d 𝕜} (hM : M.IsHermitian) (f : ℝ → ℝ) (hcfc : Matrix.IsHermitian (cfc f M) := cfc_predicate f M) : ∃ (e : d ≃ d), hcfc.eigenvalues = f ∘ hM.eigenvalues ∘ e := by have := hcfc.roots_charpoly_eq_eigenvalues.symm rw [hM.charpoly_cfc_eq f, Polynomial.roots_prod] at this; swap · simp [Finset.prod_ne_zero_iff, Polynomial.X_sub_C_ne_zero] simp_rw [Polynomial.roots_X_sub_C, Multiset.bind_singleton] at this have he := (Multiset.compTriple_equivOfMapUnivEq this).comp_eq simp_rw [← Function.comp_def RCLike.ofReal, ← Function.comp_def f, Function.comp_assoc] at he exact ⟨_, RCLike.ofReal_injective.comp_left he.symm⟩ ``` Example use case 2 (on top of https://github.com/leanprover-community/mathlib4/pull/29610): ```lean theorem LinearMap.Eigenbasis.μ_equiv {ι ι' R G : Type} [Fintype ι] [Fintype ι'] [CommRing R] [IsDomain R] [AddCommGroup G] [Module R G] [Module.Free R G] [Module.Finite R G] {f : Module.End R G} (B₁ : f.Eigenbasis ι) (B₂ : f.Eigenbasis ι') : ∃ e : ι ≃ ι', B₁.μ = B₂.μ ∘ e := by classical have := congr(Polynomial.roots $(B₁.charpoly_eq.symm.trans B₂.charpoly_eq)) rw [Polynomial.roots_prod, Polynomial.roots_prod] at this; rotate_left · simp [Finset.prod_ne_zero_iff, Polynomial.X_sub_C_ne_zero] · simp [Finset.prod_ne_zero_iff, Polynomial.X_sub_C_ne_zero] simp_rw [Polynomial.roots_X_sub_C, Multiset.bind_singleton] at this exact ⟨Multiset.equivOfMapUnivEq this, (Multiset.compTriple_equivOfMapUnivEq this).comp_eq.symm⟩ ``` Co-authored-by: Aristotle Harmonic --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-data	35/0	Mathlib/Data/Multiset/Fintype.lean	1	9	['Ruben-VandeVelde', 'github-actions', 'llllvvuu', 'mathlib4-merge-conflict-bot', 'vihdzp', 'wwylele']	pechersky assignee:pechersky	195-24915 6 months ago	195-24916 195 days ago	69-17408 69 days
29947	JaafarTanoukhi author:JaafarTanoukhi	feat(Combinatorics/Digraph): Maps	Ported `SimpleGraph/Maps.lean` to `Digraph/Maps.lean` for future PRs related to issue #[26771](https://github.com/leanprover-community/mathlib4/issues/26771) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-combinatorics new-contributor	476/0	Mathlib.lean,Mathlib/Combinatorics/Digraph/Maps.lean	2	2	['github-actions', 'mathlib4-merge-conflict-bot']	awainverse assignee:awainverse	195-24319 6 months ago	195-24320 195 days ago	54-82658 54 days
31356	adomani author:adomani	feat: add inspect-like functions	Produces a tree-like formatting for `Syntax`, `Expr` and `InfoTree`. Especially for the `InfoTree`s, there are many parts of it that do not get printed. For instance, this is how the `InfoTree`s of `set_option linter.missingDocs true` get printed: ```lean inspectIT set_option linter.missingDocs true /- commandCtx \|-Info.ofCommandInfo: Lean.Elab.Command.elabSetOption, 'set_option…gDocs true' \| \|-Info.ofCompletionInfo.CompletionInfo.option 'set_option…issingDocs' \| \|-Info.ofOptionInfo: linter.missingDocs, Linter.linter.missingDocs -/ ``` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-meta	720/0	Mathlib.lean,Mathlib/Util/Inspect.lean,MathlibTest/Inspect.lean	3	3	['github-actions', 'mathlib4-merge-conflict-bot', 'plp127']	kim-em assignee:kim-em	195-19340 6 months ago	195-19341 195 days ago	11-61557 11 days
26890	robin-carlier author:robin-carlier	feat(CategoryTheory/Monoidal/DayConvolution): more API for `DayFunctor`	We provide some lemmas that helps characterizing the monoidal structure on `DayFunctor`, they are special cases of the lemmas for `LawfulDayConvolutionMonoidalCategoryStruct`. --- - [x] depends on: #26824 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory	1372/19	Mathlib.lean,Mathlib/CategoryTheory/Functor/KanExtension/Basic.lean,Mathlib/CategoryTheory/Monoidal/DayConvolution.lean,Mathlib/CategoryTheory/Monoidal/DayConvolution/DayFunctor.lean	4	5	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	194-83967 6 months ago	unknown	unknown
26912	pechersky author:pechersky	chore(Algebra/Ring/Subring): simp tag `Subring.smul_def`	s-multiplying by a subtype is easiest to manipulate when both terms are in the ambient type. Many places that had to use the _def lemma for a rewrite, or to include it in a simp set, no longer have to. Ported from #25308 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) I found this being not-simp frustrating when talking about submodules over a valuation subring.	merge-conflict t-algebra label:t-algebra$	67/66	Mathlib/Algebra/Algebra/Subalgebra/Basic.lean,Mathlib/Algebra/Field/Subfield/Basic.lean,Mathlib/Algebra/Group/Subgroup/Actions.lean,Mathlib/Algebra/Group/Submonoid/MulAction.lean,Mathlib/Algebra/Module/LocalizedModule/Basic.lean,Mathlib/Algebra/Module/LocalizedModule/Exact.lean,Mathlib/Algebra/Module/LocalizedModule/IsLocalization.lean,Mathlib/Algebra/Module/LocalizedModule/Submodule.lean,Mathlib/Algebra/Ring/Periodic.lean,Mathlib/Algebra/Ring/Subring/Basic.lean,Mathlib/Algebra/Ring/Subsemiring/Basic.lean,Mathlib/Analysis/CStarAlgebra/Basic.lean,Mathlib/FieldTheory/KummerExtension.lean,Mathlib/GroupTheory/GroupAction/Defs.lean,Mathlib/GroupTheory/GroupAction/MultiplePrimitivity.lean,Mathlib/GroupTheory/GroupAction/MultipleTransitivity.lean,Mathlib/GroupTheory/GroupAction/SubMulAction/OfFixingSubgroup.lean,Mathlib/GroupTheory/GroupAction/SubMulAction/OfStabilizer.lean,Mathlib/LinearAlgebra/RootSystem/Irreducible.lean,Mathlib/LinearAlgebra/RootSystem/WeylGroup.lean,Mathlib/RingTheory/Etale/Kaehler.lean,Mathlib/RingTheory/Ideal/Over.lean,Mathlib/RingTheory/LocalProperties/Projective.lean,Mathlib/RingTheory/Localization/InvSubmonoid.lean,Mathlib/RingTheory/OreLocalization/Basic.lean	25	26	['artie2000', 'eric-wieser', 'github-actions', 'j-loreaux', 'kckennylau', 'leanprover-bot', 'leanprover-radar', 'linesthatinterlace', 'mathlib4-merge-conflict-bot', 'pechersky']	joelriou assignee:joelriou	168-57118 5 months ago	190-6667 190 days ago	60-55888 60 days
33434	astrainfinita author:astrainfinita	chore: redefine `Finsupp.indicator` using `Finsupp.onFinset`	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data merge-conflict	6/17	Mathlib/Data/Finsupp/Indicator.lean	1	2	['github-actions', 'mathlib-merge-conflicts']	nobody	146-3657 4 months ago	53-67213 53 days ago	1-10517 1 day
33126	CoolRmal author:CoolRmal	feat: function composition preserves boundedness	This PR adds the following theorem: if the range of a function `g` is bounded above, then `g ∘ f` is bounded above for all functions `f`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order merge-conflict	12/0	Mathlib/Order/Bounds/Basic.lean	1	2	['github-actions', 'mathlib4-merge-conflict-bot']	bryangingechen assignee:bryangingechen	137-1570 4 months ago	unknown	unknown
29587	uniwuni author:uniwuni	feat(GroupTheory/Finiteness): define finitely generated semigroups	We define finitely generated semigroups and basics similarly to monoids and groups and prove that semigroups and monoids remain finitely generated when a congruence is quotiented out. This will be important when further developing semigroup theory. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-group-theory	259/14	Mathlib/Algebra/Group/Submonoid/Defs.lean,Mathlib/GroupTheory/Finiteness.lean	2	4	['github-actions', 'mathlib4-merge-conflict-bot', 'plp127', 'uniwuni']	dupuisf assignee:dupuisf	135-13139 4 months ago	237-18043 237 days ago	25-72977 25 days
29014	ShreckYe author:ShreckYe	feat(Data/List/Scan): some theorems that relate `scanl` with `foldl`	I am not sure which is the best form of `getElem_scanl_eq_foldl_take` here, so I added several alternative forms. Feel free to remove any of them if necessary.	merge-conflict t-data	35/0	Mathlib/Data/List/Scan.lean	1	15	['ShreckYe', 'github-actions', 'mathlib4-merge-conflict-bot', 'themathqueen', 'vlad902']	pechersky assignee:pechersky	130-78763 4 months ago	204-43808 204 days ago	74-59732 74 days
9820	jjaassoonn author:jjaassoonn	feat(RingTheory/GradedAlgebra/HomogeneousIdeal): generalize to homogeneous submodule	The definitions, constructions and theorems in `HomogeneousIdeal.lean` are generalized to a homogeneous submodules. So say $R$ is a ring and $M \cong \bigoplus_{i} M_i$ is an $R$-module. Then a homogeneous $R$-submodule of $M$ is an $R$-submodule $N$ such that for all $i$ and $n \in N$, $n_i \in N$. Note that this notion doesn't actually require $R$ to be graded and $M$ is a graded module. But for more interesting lemmas, we do need that $M$ is graded $R$-module. We bake the fact $R$ is graded into the definition of homogeneous submodule, otherwise, `CompleteLattice HomogeneousSubmodule` cannot find the order of synthesis (the proof depends on that $R$ is graded) All definitions/constructions/theorems have a copy for ideals as well, this is to make sure dot notation still works. The motivation of this generalization is graded quotient module --- - [x] depends on:#18728 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory	516/185	Mathlib/Algebra/Module/GradedModule.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Scheme.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Topology.lean,Mathlib/RingTheory/GradedAlgebra/Homogeneous/Ideal.lean,Mathlib/RingTheory/GradedAlgebra/Homogeneous/Submodule.lean,Mathlib/RingTheory/GradedAlgebra/Radical.lean,scripts/nolints_prime_decls.txt	7	3	['github-actions', 'leanprover-community-bot-assistant']	nobody	113-18792 3 months ago	unknown	unknown
34931	eric-wieser author:eric-wieser	perf: make TensorProduct.lift irreducible with a unification hint	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra merge-conflict label:t-algebra$	6/2	Mathlib/LinearAlgebra/TensorProduct/Basic.lean	1	7	['eric-wieser', 'github-actions', 'leanprover-radar', 'mathlib-merge-conflicts']	erdOne assignee:erdOne	109-73212 3 months ago	unknown	unknown
33020	FormulaRabbit81 author:FormulaRabbit81	chore(Topology): Deprecate file	--- - [x] depends on: #30851 deprecation [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology large-import merge-conflict	82/49	Mathlib/Topology/Compactness/HilbertCubeEmbedding.lean,Mathlib/Topology/MetricSpace/HausdorffAlexandroff.lean,Mathlib/Topology/MetricSpace/PiNat.lean	3	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	107-49823 3 months ago	unknown	unknown
33281	michelsol author:michelsol	feat(Analysis/SpecialFunctions/Integrals): integral of 1/sqrt(1-x^2) and its integrability.	Add the integral of the derivative of arcsin and its integrability. --- - [ ] depends on: #33280 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict t-analysis	59/0	Mathlib/Analysis/SpecialFunctions/Integrability/Basic.lean,Mathlib/Analysis/SpecialFunctions/Integrals/Basic.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/FundThmCalculus.lean	3	3	['github-actions', 'mathlib-dependent-issues', 'mathlib4-merge-conflict-bot']	nobody	107-18617 3 months ago	unknown	unknown
34156	zcyemi author:zcyemi	feat(Analysis/Convex/Between): add lemmas on convex combination of mem simplex interior	--- I add three lemmas of convex combinations preserving membership in the interior of a simplex. And also open a zulip thread [#mathlib4 > Best place for convex combination and simplex interior](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Best.20place.20for.20convex.20combination.20and.20simplex.20interior/with/568558406) deps: - [ ] depends on: #33852	t-analysis merge-conflict	170/0	Mathlib/Analysis/Convex/Between.lean,Mathlib/LinearAlgebra/AffineSpace/Independent.lean	2	3	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	106-80934 3 months ago	106-80934 106 days ago	0-2180 36 minutes
32918	michelsol author:michelsol	feat: define `supEdist` and `supDist`	Create a new file Topology.MetricSpace.SupDistance and define the supremal distance in (extended) metric spaces. The defined `supEdist` and `supDist` will have similar theory to the already existing `infEdist` and `infDist`. The motivation is to be able to define the radius of a minimal bounding sphere as the infimum of the supDist later. [zulip discussion here](https://leanprover.zulipchat.com/#narrow/channel/116395-maths/topic/Formalizing.20Jung's.20theorem.20and.20minimal.20bounding.20spheres)	t-topology new-contributor merge-conflict	75/0	Mathlib.lean,Mathlib/Topology/MetricSpace/SupDistance.lean	2	5	['github-actions', 'mathlib4-merge-conflict-bot', 'michelsol', 'urkud']	nobody	105-75116 3 months ago	147-67501 147 days ago	21-1998 21 days
25980	Multramate author:Multramate	refactor(Algebra/Group/Submonoid/Operations): rename restrict to domRestrict and add restrict	And update the documentation for consistency	t-group-theory merge-conflict	145/123	Mathlib/Algebra/Group/Subgroup/Basic.lean,Mathlib/Algebra/Group/Subgroup/Ker.lean,Mathlib/Algebra/Group/Submonoid/Operations.lean,Mathlib/GroupTheory/FiniteAbelian/Duality.lean,Mathlib/GroupTheory/MonoidLocalization/Basic.lean,Mathlib/GroupTheory/MonoidLocalization/Maps.lean,Mathlib/GroupTheory/MonoidLocalization/MonoidWithZero.lean,Mathlib/GroupTheory/PGroup.lean,Mathlib/GroupTheory/QuotientGroup/Basic.lean,Mathlib/GroupTheory/Transfer.lean,Mathlib/LinearAlgebra/RootSystem/WeylGroup.lean,Mathlib/NumberTheory/NumberField/CMField.lean,Mathlib/NumberTheory/NumberField/Ideal/Basic.lean,Mathlib/RingTheory/Localization/Defs.lean	14	10	['Multramate', 'copilot-pull-request-reviewer', 'github-actions', 'mathlib-merge-conflicts']	nobody	104-55062 3 months ago	104-55063 104 days ago	5-9162 5 days
25981	Multramate author:Multramate	feat(GroupTheory/GroupAction/Basic): define homomorphisms of fixed subgroups induced by homomorphisms of groups	This PR continues the work from #10126. Original PR: https://github.com/leanprover-community/mathlib4/pull/10126	t-group-theory large-import merge-conflict	218/144	Mathlib/Algebra/Group/Subgroup/Basic.lean,Mathlib/Algebra/Group/Subgroup/Ker.lean,Mathlib/Algebra/Group/Submonoid/Operations.lean,Mathlib/Algebra/Ring/Action/Submonoid.lean,Mathlib/GroupTheory/FiniteAbelian/Duality.lean,Mathlib/GroupTheory/GroupAction/Defs.lean,Mathlib/GroupTheory/MonoidLocalization/Basic.lean,Mathlib/GroupTheory/MonoidLocalization/Maps.lean,Mathlib/GroupTheory/MonoidLocalization/MonoidWithZero.lean,Mathlib/GroupTheory/PGroup.lean,Mathlib/GroupTheory/QuotientGroup/Basic.lean,Mathlib/GroupTheory/Transfer.lean,Mathlib/LinearAlgebra/RootSystem/WeylGroup.lean,Mathlib/NumberTheory/NumberField/CMField.lean,Mathlib/NumberTheory/NumberField/Ideal/Basic.lean,Mathlib/RingTheory/Localization/Defs.lean	16	8	['copilot-pull-request-reviewer', 'github-actions', 'mathlib-merge-conflicts']	nobody	104-55061 3 months ago	104-55061 104 days ago	4-78343 4 days
33795	alreadydone author:alreadydone	feat(Topology/Sheaves): LocalPredicate prerequisite for étalé spaces	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology merge-conflict	418/143	Mathlib/AlgebraicGeometry/ProjectiveSpectrum/StructureSheaf.lean,Mathlib/Geometry/Manifold/Sheaf/Smooth.lean,Mathlib/Logic/Equiv/Basic.lean,Mathlib/Topology/Sheaves/LocalPredicate.lean,Mathlib/Topology/Sheaves/Sheafify.lean,Mathlib/Topology/Sheaves/Stalks.lean	6	12	['adamtopaz', 'alreadydone', 'dagurtomas', 'github-actions', 'mathlib-merge-conflicts']	adamtopaz assignee:adamtopaz	104-32695 3 months ago	104-32696 104 days ago	34-15820 34 days
34674	Citronhat author:Citronhat	feat(Algebra/Order/Ring): replace ENNReal lemmas with WithTop versions	* Add `WithTop` versions of basic multiplicative order lemmas. * Use the new `WithTop` lemmas to replace `ENNReal` proofs and address six TODOs. * Fix a typo in the `pos_of_ne_zero` alias name.	new-contributor t-algebra merge-conflict label:t-algebra$	46/15	Mathlib/Algebra/Order/Monoid/Canonical/Defs.lean,Mathlib/Algebra/Order/Ring/WithTop.lean,Mathlib/Data/ENNReal/Operations.lean	3	5	['Citronhat', 'Ruben-VandeVelde', 'github-actions', 'mathlib-merge-conflicts']	Ruben-VandeVelde assignee:Ruben-VandeVelde	104-12565 3 months ago	104-12566 104 days ago	15-44183 15 days
33746	ster-oc author:ster-oc	feat(Algebra/Module/ZLattice): align `ZSpan.floor` to `Int.floor` API	This PR adds some of the existent lemmas about `Int.floor`, `Int.ceil` and `Int.fract` to the `ZSpan` namespace. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor merge-conflict label:t-algebra$	353/145	Mathlib/Algebra/Module/ZLattice/Basic.lean,Mathlib/Algebra/Order/Floor/Ring.lean,Mathlib/Topology/Algebra/Order/Floor.lean	3	8	['github-actions', 'joelriou', 'mathlib-merge-conflicts', 'ster-oc']	joelriou assignee:joelriou	99-29463 3 months ago	99-29463 99 days ago	6-29290 6 days
31595	astrainfinita author:astrainfinita	chore: redefine `Ideal.IsPrime`	Redefine `Ideal.IsPrime` to make it correct for non-commutative cases --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra merge-conflict label:t-algebra$	333/100	Mathlib/Algebra/Order/Ring/Ordering/Defs.lean,Mathlib/RingTheory/DedekindDomain/Ideal/Lemmas.lean,Mathlib/RingTheory/GradedAlgebra/Radical.lean,Mathlib/RingTheory/Ideal/AssociatedPrime/Basic.lean,Mathlib/RingTheory/Ideal/Maps.lean,Mathlib/RingTheory/Ideal/Maximal.lean,Mathlib/RingTheory/Ideal/MinimalPrime/Noetherian.lean,Mathlib/RingTheory/Ideal/Oka.lean,Mathlib/RingTheory/Ideal/Operations.lean,Mathlib/RingTheory/Ideal/Over.lean,Mathlib/RingTheory/Ideal/Pointwise.lean,Mathlib/RingTheory/Ideal/Prime.lean,Mathlib/RingTheory/Ideal/Prod.lean,Mathlib/RingTheory/Ideal/Quotient/Basic.lean,Mathlib/RingTheory/Ideal/Quotient/Operations.lean,Mathlib/RingTheory/IsPrimary.lean,Mathlib/RingTheory/Localization/AtPrime/Basic.lean,Mathlib/RingTheory/Localization/Ideal.lean,Mathlib/RingTheory/Polynomial/Basic.lean,Mathlib/RingTheory/PrincipalIdealDomain.lean,Mathlib/RingTheory/Spectrum/Prime/Topology.lean,Mathlib/RingTheory/Valuation/Basic.lean	22	33	['alreadydone', 'artie2000', 'astrainfinita', 'erdOne', 'github-actions', 'leanprover-bot', 'leanprover-radar', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot']	kim-em assignee:kim-em	96-39025 3 months ago	65-35681 65 days ago	52-67033 52 days
33791	PhoenixIra author:PhoenixIra	feat: Generalization of FixedPointApproximants to CompletePartialOrder	--- This PR provides a generalization of FixedPointApproximants to CompletePartialOrder. Not every theorem can be generalized, as sometimes we require additional conditions (namely `x ≤ f x`) in order to guarantee that the set is directed and thus the supremum is well-defined. This is not necessary in a CompleteLattice. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-order merge-conflict	223/100	Mathlib/Order/CompletePartialOrder.lean,Mathlib/SetTheory/Ordinal/FixedPointApproximants.lean	2	21	['PhoenixIra', 'github-actions', 'mathlib-merge-conflicts', 'vihdzp']	PhoenixIra and vihdzp assignee:PhoenixIra assignee:vihdzp	94-66197 3 months ago	94-66197 94 days ago	38-9880 38 days
26942	pechersky author:pechersky	feat(RingTheory/Valuation/ValueGroupIso): isomorphism of value groups when compatible	and also to the ValuativeRel's value group by request from comment in https://github.com/leanprover-community/mathlib4/pull/26754#issuecomment-3051770901 - [ ] depends on: #26588 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) - [x] depends on: #26939 - [x] depends on: #26940 - [x] depends on: #26941	merge-conflict t-ring-theory t-order	299/3	Mathlib.lean,Mathlib/Algebra/GroupWithZero/Range.lean,Mathlib/Algebra/Order/GroupWithZero/Range.lean,Mathlib/Algebra/Order/GroupWithZero/WithZero.lean,Mathlib/Algebra/Order/Monoid/WithTop.lean,Mathlib/RingTheory/Valuation/ValueGroupIso.lean	6	10	['faenuccio', 'github-actions', 'mathlib-dependent-issues', 'mathlib4-merge-conflict-bot', 'pechersky']	faenuccio assignee:faenuccio	92-10378 3 months ago	291-82188 291 days ago	10-67265 10 days
35042	JovanGerb author:JovanGerb	chore: remove `meta` form `import Mathlib.Tactic...`	This PR cleans up some imports of the form `import Mathlib.Tactic...`, by either removing them entirely, or removing the `meta` keyword. It should never be necessary to `meta import` a file from `Mathlib.Tactic`, because the relevant definitions should already have been marked as `meta`. The motivation is to reduce the amount of files that are `meta` imported when writing e.g. `import Mathlib`, hence reducing the amount of stuff that needs to be loaded. There are more other `meta import`s that need to be removed, but this PR is a good start. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	large-import merge-conflict	61/142	Mathlib/Algebra/BigOperators/Group/Finset/Defs.lean,Mathlib/Algebra/FreeMonoid/Basic.lean,Mathlib/Algebra/Group/Action/Hom.lean,Mathlib/Algebra/Order/Group/Unbundled/Abs.lean,Mathlib/CategoryTheory/Functor/Basic.lean,Mathlib/Data/List/ChainOfFn.lean,Mathlib/Dynamics/OmegaLimit.lean,Mathlib/GroupTheory/GroupAction/Defs.lean,Mathlib/GroupTheory/GroupAction/DomAct/Basic.lean,Mathlib/Tactic/Algebraize.lean,Mathlib/Tactic/ApplyFun.lean,Mathlib/Tactic/ArithMult.lean,Mathlib/Tactic/Bound.lean,Mathlib/Tactic/CategoryTheory/Bicategory/Datatypes.lean,Mathlib/Tactic/CategoryTheory/Bicategory/Normalize.lean,Mathlib/Tactic/CategoryTheory/Bicategory/PureCoherence.lean,Mathlib/Tactic/CategoryTheory/CheckCompositions.lean,Mathlib/Tactic/CategoryTheory/Coherence/Basic.lean,Mathlib/Tactic/CategoryTheory/Coherence/Normalize.lean,Mathlib/Tactic/CategoryTheory/Coherence/PureCoherence.lean,Mathlib/Tactic/CategoryTheory/Elementwise.lean,Mathlib/Tactic/CategoryTheory/Monoidal/Datatypes.lean,Mathlib/Tactic/CategoryTheory/Monoidal/Normalize.lean,Mathlib/Tactic/CategoryTheory/Monoidal/PureCoherence.lean,Mathlib/Tactic/CategoryTheory/ToApp.lean,Mathlib/Tactic/Choose.lean,Mathlib/Tactic/DeclarationNames.lean,Mathlib/Tactic/DefEqTransformations.lean,Mathlib/Tactic/DeriveCountable.lean,Mathlib/Tactic/DeriveFintype.lean,Mathlib/Tactic/DeriveTraversable.lean,Mathlib/Tactic/ENatToNat.lean,Mathlib/Tactic/Explode.lean,Mathlib/Tactic/Explode/Pretty.lean,Mathlib/Tactic/FinCases.lean,Mathlib/Tactic/FunProp.lean,Mathlib/Tactic/FunProp/Attr.lean,Mathlib/Tactic/FunProp/Core.lean,Mathlib/Tactic/FunProp/FunctionData.lean,Mathlib/Tactic/FunProp/Theorems.lean,Mathlib/Tactic/FunProp/Types.lean,Mathlib/Tactic/GCongr/Core.lean,Mathlib/Tactic/GRewrite/Elab.lean,Mathlib/Tactic/Group.lean,Mathlib/Tactic/IrreducibleDef.lean,Mathlib/Tactic/Lift.lean,Mathlib/Tactic/Linarith.lean,Mathlib/Tactic/Linarith/Lemmas.lean,Mathlib/Tactic/Linarith/Oracle/FourierMotzkin.lean,Mathlib/Tactic/Linarith/Oracle/SimplexAlgorithm.lean,Mathlib/Tactic/Linarith/Oracle/SimplexAlgorithm/Gauss.lean,Mathlib/Tactic/Linarith/Oracle/SimplexAlgorithm/SimplexAlgorithm.lean,Mathlib/Tactic/Linarith/Preprocessing.lean,Mathlib/Tactic/Linarith/Verification.lean,Mathlib/Tactic/LinearCombination/Lemmas.lean,Mathlib/Tactic/Linter/DeprecatedSyntaxLinter.lean,Mathlib/Tactic/Linter/DocPrime.lean,Mathlib/Tactic/Linter/DocString.lean,Mathlib/Tactic/Linter/EmptyLine.lean,Mathlib/Tactic/Linter/FlexibleLinter.lean,Mathlib/Tactic/Linter/GlobalAttributeIn.lean,Mathlib/Tactic/Linter/HashCommandLinter.lean,Mathlib/Tactic/Linter/Multigoal.lean,Mathlib/Tactic/Linter/OldObtain.lean,Mathlib/Tactic/Linter/Style.lean,Mathlib/Tactic/Linter/TextBased.lean,Mathlib/Tactic/Linter/TextBased/UnicodeLinter.lean,Mathlib/Tactic/Linter/UnusedTactic.lean,Mathlib/Tactic/Linter/UnusedTacticExtension.lean,Mathlib/Tactic/MinImports.lean,Mathlib/Tactic/MoveAdd.lean,Mathlib/Tactic/Nontriviality/Core.lean,Mathlib/Tactic/NormNum/DivMod.lean,Mathlib/Tactic/NormNum/Ineq.lean,Mathlib/Tactic/NormNum/Prime.lean,Mathlib/Tactic/Order.lean,Mathlib/Tactic/Order/CollectFacts.lean,Mathlib/Tactic/Order/Graph/Tarjan.lean,Mathlib/Tactic/PNatToNat.lean,Mathlib/Tactic/Peel.lean,Mathlib/Tactic/ProdAssoc.lean,Mathlib/Tactic/ProxyType.lean,Mathlib/Tactic/Push.lean,Mathlib/Tactic/Qify.lean,Mathlib/Tactic/RSuffices.lean,Mathlib/Tactic/Ring/Basic.lean,Mathlib/Tactic/Ring/Common.lean,Mathlib/Tactic/Ring/Compare.lean,Mathlib/Tactic/Ring/PNat.lean,Mathlib/Tactic/Simproc/Divisors.lean,Mathlib/Tactic/Simproc/FinsetInterval.lean,Mathlib/Tactic/Simps/Basic.lean,Mathlib/Tactic/Subsingleton.lean,Mathlib/Tactic/TacticAnalysis/Declarations.lean,Mathlib/Tactic/TautoSet.lean,Mathlib/Tactic/Translate/Core.lean,Mathlib/Tactic/Translate/TagUnfoldBoundary.lean,Mathlib/Tactic/Widget/Calc.lean,Mathlib/Tactic/Widget/CommDiag.lean,Mathlib/Tactic/Widget/CongrM.lean	107	9	['JovanGerb', 'dupuisf', 'github-actions', 'leanprover-radar', 'mathlib-merge-conflicts']	robin-carlier assignee:robin-carlier	82-85827 2 months ago	78-22720 78 days ago	26-44794 26 days
36495	AlexKontorovich author:AlexKontorovich	chore(Finset/NatDivisors): refactor `card_divisors_mul` and `sum_divisors_mul` to not rely on `ArithmeticFunction`	`Nat.Coprime.card_divisors_mul` and `Nat.Coprime.sum_divisors_mul` are moved to not rely on `ArithmeticFunction`. See zulip discussion here: [#mathlib4 > Library design question, e.g.`Nat.Coprime.card_divisors_mul` @ 💬](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Library.20design.20question.2C.20e.2Eg.2E.60Nat.2ECoprime.2Ecard_divisors_mul.60/near/577769899) Co-authored-by: Ziyan Wei and Aayush Rajasekaran --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	large-import t-number-theory t-algebra merge-conflict label:t-algebra$	45/14	Mathlib/Algebra/GCDMonoid/Basic.lean,Mathlib/Data/Finset/NatDivisors.lean,Mathlib/NumberTheory/ArithmeticFunction/Misc.lean	3	6	['AlexKontorovich', 'arajasek', 'github-actions', 'mathlib-merge-conflicts']	riccardobrasca assignee:riccardobrasca	82-69344 2 months ago	24-65708 24 days ago	38-64242 38 days
27534	PierreQuinton author:PierreQuinton	feat: a typeclass for `sSup`/`sInf` to be lawful	Adds lawful infima and suprema type classes. A preorder with lawful suprema: whenever a set has a least upper bound, `sSup` returns a least upper bound for that set. A preorder with lawful infima: whenever a set has a greatest lower bound, `sInf` returns a greastest lower bound for that set. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-order	121/8	Mathlib.lean,Mathlib/Order/CompleteLattice/Defs.lean,Mathlib/Order/LawfulSupInf.lean	3	26	['PierreQuinton', 'YaelDillies', 'github-actions', 'mathlib4-merge-conflict-bot', 'plp127', 'vihdzp']	nobody	79-80574 2 months ago	195-25249 195 days ago	114-37869 114 days
37530	mcdoll author:mcdoll	fix(Topology/Algebra): fix bad simps and make arguments implicit for `PointwiseConvergenceCLM`	We delete all `simps` calls in the definitions of operators on `PointwiseConvergenceCLM` and replace them with `apply_apply` lemmas that do not abuse the defeq between `SLₚₜ` and `SL`. This made the linter discover some typeclass duplications, which we remove by restructuring the file. As a consequence of the new `simp` lemmas, we can remove all `set_option backward.isDefEq.respectTransparency false in` in `Analysis.Distribution.TemperedDistribution`. Moreover, we make several arguments implicit, which can be inferred in almost all practical situations. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	not-ready-to-merge merge-conflict	88/69	Mathlib/Analysis/Distribution/TemperedDistribution.lean,Mathlib/Topology/Algebra/Module/Spaces/PointwiseConvergenceCLM.lean	2	5	['github-actions', 'jcommelin', 'mathlib-merge-conflicts', 'mcdoll']	nobody	44-29417 1 month ago	44-29418 44 days ago	14-57413 14 days
37593	IlPreteRosso author:IlPreteRosso	refactor(Data.Finset.Antidiagonal): rename set-based defs to `setAntidiagonal`	Renames set-based `Finset.mulAntidiagonal` → `setMulAntidiagonal` (and SMul/VAdd variants) to free the `mulAntidiagonal` name for the planned `HasMulAntidiagonal` typeclass. Deprecation aliases added. Supersedes #34551	t-ring-theory new-contributor merge-conflict	178/96	Mathlib/Algebra/Order/Antidiag/Prod.lean,Mathlib/Data/Finset/MulAntidiagonal.lean,Mathlib/Data/Finset/SMulAntidiagonal.lean,Mathlib/RingTheory/HahnSeries/Multiplication.lean,Mathlib/RingTheory/HahnSeries/PowerSeries.lean,Mathlib/RingTheory/HahnSeries/Summable.lean	6	3	['github-actions', 'mathlib-merge-conflicts']	nobody	44-29416 1 month ago	44-29417 44 days ago	15-58995 15 days
37444	vihdzp author:vihdzp	feat: typeclass for zero-dimensional spaces	--- - [ ] depends on: #37317 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology large-import merge-conflict	151/110	Mathlib/Topology/Algebra/ClopenNhdofOne.lean,Mathlib/Topology/Category/LightProfinite/Basic.lean,Mathlib/Topology/Category/Profinite/Basic.lean,Mathlib/Topology/Category/Profinite/CofilteredLimit.lean,Mathlib/Topology/Category/Stonean/Basic.lean,Mathlib/Topology/ClopenBox.lean,Mathlib/Topology/Order.lean,Mathlib/Topology/Order/WithTop.lean,Mathlib/Topology/Separation/CompletelyRegular.lean,Mathlib/Topology/Separation/DisjointCover.lean,Mathlib/Topology/Separation/Lemmas.lean,Mathlib/Topology/Separation/Profinite.lean,Mathlib/Topology/UniformSpace/Ultra/Basic.lean	13	17	['ADedecker', 'FernandoChu', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'vihdzp']	nobody	42-8700 1 month ago	42-9772 42 days ago	0-5190 1 hour
38239	vihdzp author:vihdzp	chore(Order/SuccPred/Limit): reorganize sections	In an effort to keep the file better organized, we move theorems which use `SuccOrder`/`PredOrder` as an assumption to a new section. No theorems have been changed. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order merge-conflict	95/110	Mathlib/Order/SuccPred/Limit.lean	1	2	['github-actions', 'mathlib-merge-conflicts']	nobody	41-58994 1 month ago	41-58995 41 days ago	2-43850 2 days
37461	grunweg author:grunweg	chore: golf using the field tactic	--- In the spirit of #31314. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	32/43	Counterexamples/NowhereDifferentiable.lean,Mathlib/Analysis/Calculus/Monotone.lean,Mathlib/Analysis/Complex/BorelCaratheodory.lean,Mathlib/Analysis/MeanInequalities.lean,Mathlib/Analysis/Normed/Field/Lemmas.lean,Mathlib/Analysis/SpecialFunctions/Complex/LogBounds.lean,Mathlib/Analysis/SpecialFunctions/Elliptic/Weierstrass.lean,Mathlib/Analysis/SpecialFunctions/Integrals/Basic.lean,Mathlib/InformationTheory/KullbackLeibler/Basic.lean,Mathlib/LinearAlgebra/Lagrange.lean,Mathlib/MeasureTheory/Integral/MeanValue.lean,Mathlib/NumberTheory/ModularForms/Discriminant.lean,Mathlib/NumberTheory/ModularForms/EisensteinSeries/E2/Defs.lean,Mathlib/NumberTheory/ModularForms/EisensteinSeries/E2/MDifferentiable.lean,Mathlib/NumberTheory/ModularForms/QExpansion.lean,Mathlib/Probability/CentralLimitTheorem.lean,Mathlib/Probability/Distributions/Gaussian/CharFun.lean,Mathlib/RepresentationTheory/Homological/GroupCohomology/Hilbert90.lean,Mathlib/RingTheory/PowerSeries/Exp.lean,Mathlib/Topology/UnitInterval.lean	20	5	['github-actions', 'grunweg', 'j-loreaux', 'mathlib-merge-conflicts']	nobody	39-58698 1 month ago	39-58699 39 days ago	22-57584 22 days
37774	weisbrja author:weisbrja	fix: change variables in `bicompl` to `Sort*` and add missing theorem mentioned in `bicompl` docs	[#mathlib4 > Why does Mathlib use Type* instead of Sort* in some places?](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Why.20does.20Mathlib.20use.20Type.2A.20instead.20of.20Sort.2A.20in.20some.20places.3F/with/583882342) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-logic merge-conflict	6/1	Mathlib/Logic/Function/Basic.lean	1	8	['github-actions', 'kbuzzard', 'leanprover-radar', 'mathlib-merge-conflicts', 'weisbrja']	nobody	35-72326 1 month ago	35-72327 35 days ago	19-66334 19 days
36740	euprunin author:euprunin	chore: golf using `grind`	The goal of this PR is to decrease the number of times lemmas are called explicitly. Any decrease in compilation time is a welcome side effect, although it is not a primary objective. Trace profiling results (differences <30 ms considered measurement noise): * `AlgebraicGeometry.Scheme.isBasis_affineOpens`: unchanged 🎉 * `SimpleGraph.Walk.takeUntil_eq_take`: 263 ms before, 180 ms after 🎉 * `SimpleGraph.Walk.dropUntil_eq_drop`: 382 ms before, 261 ms after 🎉 * `Int.image_Ico_emod`: unchanged 🎉 * `Equiv.Perm.ofSubtype_swap_eq`: unchanged 🎉 Profiled using `set_option trace.profiler true in`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	7/33	Mathlib/AlgebraicGeometry/AffineScheme.lean,Mathlib/Combinatorics/SimpleGraph/Walk/Decomp.lean,Mathlib/Data/Int/Interval.lean,Mathlib/GroupTheory/Perm/Support.lean	4	8	['artie2000', 'chenson2018', 'github-actions', 'mathlib-merge-conflicts']	nobody	33-61789 1 month ago	33-61790 33 days ago	42-86188 42 days
37603	Parcly-Taxel author:Parcly-Taxel	refactor: review of `SetSemiring`	* Rename `Set.up` and `SetSemiring.down` to `SetSemiring.ofSet` and `SetSemiring.toSet` respectively. Unprotect both and make them equivalences, following `FreeMonoid`. * Derive `CompleteAtomicBooleanAlgebra` for `SetSemiring` immediately. * Add `imageHom_id` and `imageHom_comp`. The three existing lemmas about `imageHom` are coalesced into `imageHom_apply`. Ultimately inspired by https://github.com/leanprover-community/mathlib4/pull/36934#issuecomment-4183475568.	maintainer-merge merge-conflict	120/165	Mathlib/Algebra/Algebra/Operations.lean,Mathlib/Data/Set/Semiring.lean	2	42	['Parcly-Taxel', 'YaelDillies', 'eric-wieser', 'github-actions', 'mathlib-merge-conflicts', 'sgouezel']	nobody	33-53179 1 month ago	33-53180 33 days ago	22-34679 22 days
38329	jcommelin author:jcommelin	chore: tighten down public/exposed API of AlgebraicClosure	This PR tightens down the API of AlgebraicClosure, by making few parts of FieldTheory/IsAlgClosed/AlgebraicClosure.lean public and/or exposed. We still need to expose the main definition. It would be great if we can unexpose it in the future. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra merge-conflict label:t-algebra$	73/53	Mathlib/Algebra/Lie/TraceForm.lean,Mathlib/FieldTheory/AxGrothendieck.lean,Mathlib/FieldTheory/Differential/Liouville.lean,Mathlib/FieldTheory/IsAlgClosed/AlgebraicClosure.lean,Mathlib/ModelTheory/Algebra/Field/IsAlgClosed.lean,Mathlib/RingTheory/Discriminant.lean,Mathlib/RingTheory/IntegralClosure/IntegralRestrict.lean,Mathlib/RingTheory/Norm/Transitivity.lean,Mathlib/RingTheory/Trace/Basic.lean	9	26	['eric-wieser', 'github-actions', 'jcommelin', 'kbuzzard', 'leanprover-radar', 'mathlib-merge-conflicts', 'plp127', 'riccardobrasca']	nobody	33-53162 1 month ago	33-53163 33 days ago	7-34485 7 days
37819	YellPika author:YellPika	feat(Order/OmegaCompletePartialOrder): add `OmegaCompletePartialOrder` instance for `WithBot` with basic `ωScottContinuous` lemmas	This is a modification of #34093. See #34093 for details. --- - [x] depends on: #33941 - [x] depends on: #37258 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-order merge-conflict	337/10	Mathlib/Algebra/Order/Ring/WithTop.lean,Mathlib/Analysis/BoxIntegral/Box/Basic.lean,Mathlib/Order/Monotone/Basic.lean,Mathlib/Order/OmegaCompletePartialOrder.lean,Mathlib/Order/TypeTags.lean,Mathlib/Order/WithBot.lean	6	5	['Komyyy', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	Komyyy assignee:Komyyy	32-36387 1 month ago	32-36387 32 days ago	22-4315 22 days
37053	artie2000 author:artie2000	refactor(Analysis/Convex/Cone): use `PointedCone` in Riesz extension theorem	Change the statement of the Riesz extension theorem to take a `PointedCone` rather than a `ConvexCone`. This PR is part of a series replacing `ConvexCone` with `PointedCone`. https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Replacing.20.60ConvexCone.60.20with.20.60PointedCone.60/near/581184307 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-convex-geometry maintainer-merge merge-conflict	15/12	Mathlib/Analysis/Convex/Cone/Extension.lean,Mathlib/Geometry/Convex/Cone/Pointed.lean	2	9	['YaelDillies', 'artie2000', 'github-actions', 'mathlib-merge-conflicts', 'ocfnash']	nobody	21-61392 21 days ago	21-61393 21 days ago	46-64967 46 days
37553	grunweg author:grunweg	chore: golf using .ne and friends	ne_of_gt -> .ne' ne_of_lt -> .ne le_of_lt -> .le Drive-by golfs using gcongr and positivity and been split into separate PRs. --- - [x] depends on: #37462 - [x] depends on: #37715 - [x] depends on: #37554 - [x] depends on: #37845 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	302/321	Archive/Imo/Imo1981Q3.lean,Archive/Imo/Imo2011Q3.lean,Archive/Imo/Imo2013Q5.lean,Archive/Imo/Imo2019Q4.lean,Archive/Wiedijk100Theorems/CubingACube.lean,Counterexamples/DiscreteTopologyNonDiscreteUniformity.lean,Counterexamples/NowhereDifferentiable.lean,Counterexamples/TopologistsSineCurve.lean,Mathlib/Algebra/BigOperators/Fin.lean,Mathlib/Algebra/BigOperators/Group/List/Lemmas.lean,Mathlib/Algebra/CharP/Defs.lean,Mathlib/Algebra/Group/Fin/Basic.lean,Mathlib/Algebra/Group/Pointwise/Set/Finite.lean,Mathlib/Algebra/Lie/Nilpotent.lean,Mathlib/Algebra/Module/Torsion/Basic.lean,Mathlib/Algebra/Module/ZLattice/Basic.lean,Mathlib/Algebra/Module/ZLattice/Covolume.lean,Mathlib/Algebra/Order/Antidiag/Nat.lean,Mathlib/Algebra/Order/Archimedean/Basic.lean,Mathlib/Algebra/Order/Archimedean/Class.lean,Mathlib/Algebra/Order/BigOperators/Group/Multiset.lean,Mathlib/Algebra/Order/BigOperators/GroupWithZero/Finset.lean,Mathlib/Algebra/Order/CauSeq/Basic.lean,Mathlib/Algebra/Order/CauSeq/BigOperators.lean,Mathlib/Algebra/Order/CompleteField.lean,Mathlib/Algebra/Order/Field/Basic.lean,Mathlib/Algebra/Order/GroupWithZero/Range.lean,Mathlib/Algebra/Order/GroupWithZero/Unbundled/Basic.lean,Mathlib/Algebra/Order/Interval/Set/Instances.lean,Mathlib/Algebra/Order/Module/HahnEmbedding.lean,Mathlib/Algebra/Order/Ring/WithTop.lean,Mathlib/Algebra/Order/Round.lean,Mathlib/Algebra/Order/ToIntervalMod.lean,Mathlib/Algebra/Polynomial/DenomsClearable.lean,Mathlib/Algebra/Polynomial/EraseLead.lean,Mathlib/Algebra/Polynomial/Monic.lean,Mathlib/Algebra/QuadraticDiscriminant.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Proper.lean,Mathlib/Analysis/Analytic/Composition.lean,Mathlib/Analysis/Analytic/Inverse.lean,Mathlib/Analysis/Analytic/OfScalars.lean,Mathlib/Analysis/Analytic/Uniqueness.lean,Mathlib/Analysis/Asymptotics/ExpGrowth.lean,Mathlib/Analysis/Asymptotics/LinearGrowth.lean,Mathlib/Analysis/Asymptotics/SpecificAsymptotics.lean,Mathlib/Analysis/Asymptotics/TVS.lean,Mathlib/Analysis/BoxIntegral/Basic.lean,Mathlib/Analysis/BoxIntegral/Partition/Tagged.lean,Mathlib/Analysis/Calculus/BumpFunction/FiniteDimension.lean,Mathlib/Analysis/Calculus/ContDiff/Defs.lean,Mathlib/Analysis/Calculus/ContDiff/FTaylorSeries.lean,Mathlib/Analysis/Calculus/DerivativeTest.lean,Mathlib/Analysis/Calculus/FDeriv/Extend.lean,Mathlib/Analysis/Calculus/FDeriv/Measurable.lean,Mathlib/Analysis/Calculus/IteratedDeriv/Defs.lean,Mathlib/Analysis/Calculus/LHopital.lean,Mathlib/Analysis/Complex/Exponential.lean,Mathlib/Analysis/Complex/Hadamard.lean,Mathlib/Analysis/Complex/OpenMapping.lean,Mathlib/Analysis/Complex/Poisson.lean,Mathlib/Analysis/Complex/Trigonometric.lean,Mathlib/Analysis/Convex/Between.lean,Mathlib/Analysis/Convex/Caratheodory.lean,Mathlib/Analysis/Convex/Combination.lean,Mathlib/Analysis/Convex/Gauge.lean,Mathlib/Analysis/Convex/Radon.lean,Mathlib/Analysis/Convex/SpecificFunctions/Deriv.lean,Mathlib/Analysis/Convolution.lean,Mathlib/Analysis/InnerProductSpace/Subspace.lean,Mathlib/Analysis/LocallyConvex/WithSeminorms.lean,Mathlib/Analysis/MeanInequalities.lean,Mathlib/Analysis/MeanInequalitiesPow.lean,Mathlib/Analysis/MellinInversion.lean,Mathlib/Analysis/MellinTransform.lean,Mathlib/Analysis/Normed/Field/Approximation.lean,Mathlib/Analysis/Normed/Module/FiniteDimension.lean,Mathlib/Analysis/Normed/Operator/ContinuousAlgEquiv.lean,Mathlib/Analysis/Normed/Ring/Units.lean,Mathlib/Analysis/Normed/Unbundled/IsPowMulFaithful.lean,Mathlib/Analysis/Normed/Unbundled/SmoothingSeminorm.lean,Mathlib/Analysis/Normed/Unbundled/SpectralNorm.lean,Mathlib/Analysis/Oscillation.lean,Mathlib/Analysis/Real/Hyperreal.lean,Mathlib/Analysis/Real/Pi/Bounds.lean,Mathlib/Analysis/SpecialFunctions/ContinuousFunctionalCalculus/Rpow/IntegralRepresentation.lean,Mathlib/Analysis/SpecialFunctions/Log/Basic.lean,Mathlib/Analysis/SpecialFunctions/PolarCoord.lean,Mathlib/Analysis/SpecialFunctions/Pow/NNReal.lean,Mathlib/Analysis/SpecialFunctions/Pow/Real.lean,Mathlib/Analysis/SpecialFunctions/Trigonometric/Basic.lean,Mathlib/Data/EReal/Inv.lean,Mathlib/Data/Finset/Image.lean,Mathlib/Data/Int/Interval.lean,Mathlib/Data/Int/ModEq.lean,Mathlib/Data/Nat/Bitwise.lean,Mathlib/Data/Nat/Lattice.lean,Mathlib/Data/Nat/Log.lean,Mathlib/Data/Nat/Multiplicity.lean,Mathlib/Data/Real/ConjExponents.lean,Mathlib/Dynamics/Circle/RotationNumber/TranslationNumber.lean	114	7	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	19-52678 19 days ago	19-52678 19 days ago	13-56900 13 days
39229	grunweg author:grunweg	dev: towards `fun_prop` on manifolds	--- - [ ] depends on: #39226 Rebased version of #31580. Meant to be a prototype that demonstrate how this could possibly work. Not functional yet; waiting on cache to continue. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta merge-conflict	305/1	Mathlib/Geometry/Manifold/Notation.lean,Mathlib/Tactic/FunProp/Core.lean,MathlibTest/DifferentialGeometry/FunPropM.lean,MathlibTest/fun_prop_dev.lean	4	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	17-33568 17 days ago	unknown	unknown
39329	lecopivo author:lecopivo	feat(fun_prop): eager application of transition theorems for fun_prop	For properties like Integrable we want to apply transition theorems(like Continuous -> Integrable) eagerly --- This is a change necessary in preparation for making `fun_prop` work for integrability. --> [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta merge-conflict	93/30	Mathlib/Tactic/FunProp/Attr.lean,Mathlib/Tactic/FunProp/Core.lean,Mathlib/Tactic/FunProp/Decl.lean,MathlibTest/FunPropMinimal.lean	4	14	['b-mehta', 'github-actions', 'lecopivo', 'mathlib-merge-conflicts']	JovanGerb assignee:JovanGerb	14-80386 14 days ago	17-7934 17 days ago	1-34273 1 day
37584	kennethgoodman author:kennethgoodman	feat(Data/Nat/Fib): formalize Lamé's theorem	## Summary Formalize [Lamé's theorem](https://en.wikipedia.org/wiki/Lam%C3%A9%27s_theorem) (1844), the founding result of computational complexity theory. Lamé's Theorem: If the Euclidean algorithm on inputs `(a, b)` with `b ≤ a` takes `n + 1` division steps, then `b ≥ fib(n + 1)` and `a ≥ fib(n + 2)`. ### New definitions - `Nat.euclidSteps`: counts the number of division steps in the Euclidean algorithm on natural number inputs. ### New theorems - `Nat.fib_le_of_euclidSteps`: the main Lamé bound — Fibonacci lower bound on inputs given a step count. - `Nat.euclidSteps_le_of_lt_fib`: the contrapositive — step count upper bound given a Fibonacci bound on the smaller input. - `Nat.add_mod_le`: helper lemma that `b + a % b ≤ a` when `b ≤ a` and `0 < b`. ### Proof strategy Induction on `n`, tracking both elements of the pair. The key insight is that each Euclidean step replaces `(a, b)` with `(b, a % b)`, and since `a ≥ b + a % b` (because `a / b ≥ 1`), the Fibonacci recurrence `fib(n+3) = fib(n+2) + fib(n+1)` matches the structure of the algorithm. ### References - Gabriel Lamé, Note sur la limite du nombre des divisions dans la recherche du plus grand commun diviseur entre deux nombres entiers, Comptes rendus de l'Académie des sciences, 1844. --- ### AI usage disclosure Per the [Mathlib AI guidelines](https://leanprover-community.github.io/contribute/index.html#use-of-ai): Claude Code (Claude Opus 4.6) was used to assist with writing the Lean 4 proof code, fixing tactic errors, and drafting this PR description. The mathematical proof (induction on step count, tracking both pair elements through the Fibonacci recurrence) was designed by hand and verified on paper before formalization. I have reviewed and understand every line of the resulting Lean code and can explain all proof steps. --- - [x] builds cleanly (`lake build Mathlib.Data.Nat.Fib.Lame`) - [x] no `sorry` - [x] lines ≤ 100 characters, no trailing whitespace - [x] `autoImplicit false` - [x] docstrings on all public declarations	new-contributor LLM-generated t-data merge-conflict	121/0	Mathlib.lean,Mathlib/Data/Nat/Basic.lean,Mathlib/Data/Nat/Fib/Basic.lean,Mathlib/Data/Nat/Fib/Lame.lean,docs/1000.yaml	5	25	['euprunin', 'github-actions', 'kennethgoodman', 'mathlib-merge-conflicts', 'vihdzp', 'wwylele']	TwoFX assignee:TwoFX	14-69059 14 days ago	14-69060 14 days ago	44-53174 44 days
38036	JovanGerb author:JovanGerb	feat: `NSMul`/`NPow` type class	This PR is adds `NSMul`, `NPow`, `ZSMul` and `ZPow` classes for the `nsmul`, `npow`, `zsmul`, `zpow` data fields. This has a few advantages: - If you first declare a `SMul` instance, then you don't need to manually write `nsmul := (· • ·)` and `zsmul := (· • ·)` . For `Pow`, the extra benefit is that inferring the instance is preferred over the default field `npowRecAuto`. So this helps avoid accidental diamonds. - If you first declare a `SMul` instance on a type synonym, then `inferInstanceAs` will infer the `nsmul` field from the `SMul` instance. This makes it easier to avoid diamonds on type synonyms like `Matrix` and `MonoidAlgebra`. - The not-yet-merged instance diamond linter will be able to detect cases where the `NSMul` and `SMul` classes do not agree. In the process of making this PR, I have identified two existing `NPow` diamonds: - In `Mathlib.Algebra.Order.Positive.Field`, there were two conflicting `NPow` instances. - For `Fin`, there are two conflicting `NPow` instances. I have overwritten the one in core lean with the one from mathlib that is more computationally efficient. TODO: the same for `QSMul` and `NNQSMul`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	276/273	Mathlib/Algebra/Colimit/DirectLimit.lean,Mathlib/Algebra/FreeAlgebra.lean,Mathlib/Algebra/Group/Action/Opposite.lean,Mathlib/Algebra/Group/Defs.lean,Mathlib/Algebra/Group/Ext.lean,Mathlib/Algebra/Group/Int/Defs.lean,Mathlib/Algebra/Group/Opposite.lean,Mathlib/Algebra/Group/Prod.lean,Mathlib/Algebra/Group/Submonoid/Membership.lean,Mathlib/Algebra/Group/TypeTags/Basic.lean,Mathlib/Algebra/Group/Units/Defs.lean,Mathlib/Algebra/GroupWithZero/Action/Opposite.lean,Mathlib/Algebra/Module/NatInt.lean,Mathlib/Algebra/MonoidAlgebra/Defs.lean,Mathlib/Algebra/Order/Monoid/Unbundled/WithTop.lean,Mathlib/Algebra/Order/Positive/Field.lean,Mathlib/Algebra/Order/Ring/Archimedean.lean,Mathlib/Algebra/Order/Ring/WithTop.lean,Mathlib/Algebra/Ring/MinimalAxioms.lean,Mathlib/Algebra/RingQuot.lean,Mathlib/CategoryTheory/Triangulated/Basic.lean,Mathlib/Data/BitVec.lean,Mathlib/Data/Complex/Basic.lean,Mathlib/Data/Rat/Defs.lean,Mathlib/Data/ZMod/Defs.lean,Mathlib/Data/ZMod/IntUnitsPower.lean,Mathlib/FieldTheory/RatFunc/Basic.lean,Mathlib/GroupTheory/GroupAction/Hom.lean,Mathlib/LinearAlgebra/Matrix/Defs.lean,Mathlib/LinearAlgebra/Matrix/ZPow.lean,Mathlib/LinearAlgebra/TensorProduct/Basic.lean,Mathlib/LinearAlgebra/TensorProduct/Defs.lean,Mathlib/NumberTheory/ArithmeticFunction/Defs.lean,Mathlib/RingTheory/PolynomialLaw/Basic.lean,Mathlib/RingTheory/Valuation/ValuativeRel/Basic.lean,Mathlib/SetTheory/Cardinal/Order.lean,Mathlib/Tactic/Abel.lean,Mathlib/Tactic/Translate/ToAdditive.lean,Mathlib/Topology/Algebra/GroupCompletion.lean,Mathlib/Topology/Algebra/Module/LinearMap.lean,MathlibTest/instance_diamonds.lean	41	17	['JovanGerb', 'eric-wieser', 'github-actions', 'jcommelin', 'leanprover-radar', 'mathlib-merge-conflicts', 'vihdzp']	nobody	12-52622 12 days ago	12-52623 12 days ago	29-38022 29 days
39509	mcdoll author:mcdoll	chore(Topology): add `push/pull_end` tags for CLMs	Simpsets were introduced in #38359, see also #39508 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology merge-conflict	2/0	Mathlib/Topology/Algebra/Module/LinearMap.lean	1	2	['github-actions', 'mathlib-merge-conflicts']	j-loreaux assignee:j-loreaux	12-48559 12 days ago	12-52607 12 days ago	3-38611 3 days
36774	euprunin author:euprunin	chore: replace long terminal `rw […]`:s (≥4 lemmas) with bare `simp`:s	The goal of this PR is to decrease the number of times lemmas are called explicitly. Any decrease in compilation time is a welcome side effect, although it is not a primary objective. Trace profiling results (differences <30 ms considered measurement noise): * `Finset.lcm_union`: unchanged 🎉 * `Finset.gcd_union`: unchanged 🎉 * `Polynomial.derivative_eval₂_C`: unchanged 🎉 * `Polynomial.expand_pow`: unchanged 🎉 * `Cardinal.mk_real`: unchanged 🎉 * `Real.log_zpow`: unchanged 🎉 * `Matroid.eRank_le_encard_add_eRk_compl`: unchanged 🎉 * `DFinsupp.single_tsub`: unchanged 🎉 * `EReal.inv_neg`: unchanged 🎉 * `Finsupp.toMultiset_map`: unchanged 🎉 * `Finsupp.single_tsub`: unchanged 🎉 * `Multiset.countP_map`: unchanged 🎉 * `Nat.ascFactorial_eq_factorial_mul_choose'`: unchanged 🎉 * `Real.sign_intCast`: unchanged 🎉 * `Real.volume_eball`: unchanged 🎉 * `Real.volume_closedEBall`: unchanged 🎉 * `LFunction_ne_zero_of_not_quadratic_or_ne_one`: 295 ms before, 152 ms after 🎉 * `hasSum_one_div_nat_pow_mul_cos`: unchanged 🎉 * `inv_eq_of_aeval_divX_ne_zero`: unchanged 🎉 * `AlgebraicIndependent.aeval_comp_mvPolynomialOptionEquivPolynomialAdjoin`: unchanged 🎉 * `Ordinal.deriv_mul_eq_opow_omega0_mul`: unchanged 🎉 Profiled using `set_option trace.profiler true in`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	22/24	Mathlib/Algebra/GCDMonoid/Finset.lean,Mathlib/Algebra/Polynomial/Derivative.lean,Mathlib/Algebra/Polynomial/Expand.lean,Mathlib/Analysis/Real/Cardinality.lean,Mathlib/Analysis/SpecialFunctions/Log/Basic.lean,Mathlib/Combinatorics/Matroid/Rank/ENat.lean,Mathlib/Data/DFinsupp/Order.lean,Mathlib/Data/EReal/Inv.lean,Mathlib/Data/Finsupp/Multiset.lean,Mathlib/Data/Finsupp/Order.lean,Mathlib/Data/Multiset/Filter.lean,Mathlib/Data/Nat/Choose/Basic.lean,Mathlib/Data/Real/Sign.lean,Mathlib/MeasureTheory/Measure/Lebesgue/Basic.lean,Mathlib/NumberTheory/LSeries/Nonvanishing.lean,Mathlib/NumberTheory/ZetaValues.lean,Mathlib/RingTheory/Algebraic/Basic.lean,Mathlib/RingTheory/AlgebraicIndependent/Basic.lean,Mathlib/SetTheory/Ordinal/FixedPoint.lean	19	3	['artie2000', 'euprunin', 'github-actions', 'mathlib-merge-conflicts']	nobody	9-77996 9 days ago	9-77997 9 days ago	66-82463 66 days
38018	matthewjasper author:matthewjasper	feat(Algebra): expand Subalgebra.restrictScalars API	Add an instance for the original algebra structure, the implied scalar tower instances, and the algebra equivalence with the original subalgebra. Use this to remove some `set_option backward.isDefEq.respectTransparency`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory merge-conflict	53/14	Mathlib/Algebra/Algebra/Subalgebra/Tower.lean,Mathlib/RingTheory/AlgebraicIndependent/TranscendenceBasis.lean,Mathlib/RingTheory/Finiteness/Basic.lean,Mathlib/RingTheory/IntegralClosure/IsIntegralClosure/Basic.lean	4	6	['eric-wieser', 'github-actions', 'leanprover-radar', 'mariainesdff', 'mathlib-merge-conflicts']	mariainesdff assignee:mariainesdff	9-76670 9 days ago	9-76670 9 days ago	39-67977 39 days
38882	yuanyi-350 author:yuanyi-350	refactor(MeasureTheory): golf `Mathlib/MeasureTheory/Function/AEMeasurableOrder`	- replaces the manual `μ t = 0` to `ae` conversion with `measure_eq_zero_iff_ae_notMem` - rewrites the two density arguments in `aemeasurable_of_exist_almost_disjoint_supersets` using `s_dense.exists_between` and `mem_iUnion₂` Extracted from #38104 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	codex LLM-generated t-measure-probability merge-conflict	7/18	Mathlib/MeasureTheory/Function/AEMeasurableOrder.lean	1	3	['github-actions', 'mathlib-merge-conflicts', 'yuanyi-350']	kex-y assignee:kex-y	9-76278 9 days ago	9-76279 9 days ago	20-13133 20 days
37956	artie2000 author:artie2000	feat(Algebra/Polynomial): lemmas about polynomial degree	* Add various small lemmas about polynomial degree --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra merge-conflict label:t-algebra$	28/5	Mathlib/Algebra/Polynomial/Degree/Defs.lean,Mathlib/Algebra/Polynomial/Degree/Operations.lean,Mathlib/Algebra/Polynomial/FieldDivision.lean,Mathlib/Algebra/Polynomial/Monic.lean,MathlibTest/hintAll.lean	5	8	['artie2000', 'github-actions', 'mathlib-merge-conflicts', 'vihdzp']	kim-em assignee:kim-em	7-39688 7 days ago	7-39689 7 days ago	43-34984 43 days
38989	grunweg author:grunweg	chore: remove `(d)simp only []`	Either remove them (when they were unnecessary), or replace by something more low-level. --- I'm happy to make them `simp only` instead, if that is preferred. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	10/17	Counterexamples/AharoniKorman.lean,Mathlib/Analysis/SpecialFunctions/Integrals/PosLogEqCircleAverage.lean,Mathlib/CategoryTheory/Limits/Fubini.lean,Mathlib/Computability/PartrecCode.lean,Mathlib/Computability/RE.lean,Mathlib/Computability/TuringMachine/Config.lean,Mathlib/Computability/TuringMachine/StackTuringMachine.lean,Mathlib/LinearAlgebra/Matrix/Basis.lean,Mathlib/MeasureTheory/Covering/Besicovitch.lean,Mathlib/MeasureTheory/Measure/Restrict.lean,Mathlib/ModelTheory/Encoding.lean	11	5	['b-mehta', 'github-actions', 'grunweg', 'mathlib-merge-conflicts']	nobody	6-52804 6 days ago	6-52805 6 days ago	20-55633 20 days
37723	xgenereux author:xgenereux	feat(Adjoin/Polynomial/Transcendental): Adjoining transcendental elements	This PR establishes some basic properties about `A[y]` when `y` is transcendental over `A`. These are mostly just carried over from `A[X]`. - Move `algEquivOfTranscendental` in the newly created file `Mathlib.RingTheory.Adjoin.Polynomial.Transcendental` - Add `Algebra.adjoin.evalOfTranscendental`. This is technically very similar to `Algebra.adjoin.liftSingleton` but the definition is much simpler. It is also currently more general in the sense that it doesn't require `A` to be a field. - Some basic instances from `Polynomial`. Note that these are actually theorems because of the hypothesis `(h : Transcendental R s)` everywhere. I've also added a `Fact` version to allow the possibility of instances. Last note : I initially considered adding some results in `RingTheory.Polynomial.Quotient` where I golfed the file a tiny bit. I removed the unused results but kept the golf. Co-authored-by: María Inés de Frutos Fernández <[mariaines.dff@gmail.com](mailto:mariaines.dff@gmail.com)> --- - [ ] depends on: #36439 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory merge-conflict	135/65	Mathlib.lean,Mathlib/Algebra/Algebra/Subalgebra/Lattice.lean,Mathlib/FieldTheory/RatFunc/AsPolynomial.lean,Mathlib/RingTheory/Adjoin/Polynomial/Basic.lean,Mathlib/RingTheory/Adjoin/Polynomial/Bivariate.lean,Mathlib/RingTheory/Adjoin/Polynomial/Transcendental.lean,Mathlib/RingTheory/Algebraic/Basic.lean,Mathlib/RingTheory/Polynomial/Quotient.lean	8	5	['github-actions', 'leanprover-radar', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'riccardobrasca']	nobody	6-8866 6 days ago	unknown	unknown
39676	joneugster author:joneugster	chore: move test files and recapitalise filennames	Continuation of #39674. Renames all test files to use UpperCamelCase. Moves a few files to a folder according to the location of the tested file. --- While fixing capitalisation on all filenames, this PR makes no effort to sort all test files into according folders. This will be happening in follow-ups. - [x] depends on: #39681 - [x] depends on: #39682 - [ ] depends on: #39683 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	file-removed merge-conflict	22/22	MathlibTest/AesopCat.lean,MathlibTest/Algebra/Algebra/Rat.lean,MathlibTest/Algebra/Polynomial.lean,MathlibTest/Algebra/Quaternion.lean,MathlibTest/Data/DFinsupp/DFinsuppMultiLinear.lean,MathlibTest/Data/DFinsupp/Notation.lean,MathlibTest/Data/Fin/VecNotation.lean,MathlibTest/Data/FunLike.lean,MathlibTest/Data/Real.lean,MathlibTest/Data/ZMod.lean,MathlibTest/DeriveCountable.lean,MathlibTest/DeriveCountableModule.lean,MathlibTest/DeriveEncodable.lean,MathlibTest/ENatToNat.lean,MathlibTest/EvalElab.lean,MathlibTest/FailIfNoProgress.lean,MathlibTest/FastInstance.lean,MathlibTest/FinsetBuilder.lean,MathlibTest/FinsetRepr.lean,MathlibTest/FinsuppNotation.lean,MathlibTest/FormatTable.lean,MathlibTest/ImportAll.lean,MathlibTest/InstanceDiamonds.lean,MathlibTest/InstanceDiamonds/Analysis/Normed/Field/WithAbs.lean,MathlibTest/InstanceDiamonds/Data/Complex/Module.lean,MathlibTest/InstanceDiamonds/FieldTheory/IsAlgClosed/AlgebraicClosure.lean,MathlibTest/InstanceDiamonds/FieldTheory/SplittingField/Construction.lean,MathlibTest/InstanceDiamonds/Normed.lean,MathlibTest/JacobiSymbol.lean,MathlibTest/Lean/Tactic/Grind/AC.lean,MathlibTest/Lean/Tactic/Grind/CC.lean,MathlibTest/Lean/Tactic/Grind/Field.lean,MathlibTest/Lean/Tactic/Grind/FieldInstance.lean,MathlibTest/Lean/Tactic/Grind/Grobner.lean,MathlibTest/Lean/Tactic/Grind/Linarith.lean,MathlibTest/Lean/Tactic/Grind/Lint.lean,MathlibTest/Lean/Tactic/Grind/NatCastInstance.lean,MathlibTest/Lean/Tactic/Grind/OrderedRing.lean,MathlibTest/Lean/Tactic/Grind/PairwiseDisjoint.lean,MathlibTest/Lean/Tactic/Grind/Panic.lean,MathlibTest/Lean/Tactic/Grind/Ring.lean,MathlibTest/Lean/Tactic/Grind/Set.lean,MathlibTest/Lean/Tactic/Grind/Trig.lean,MathlibTest/Lean/Tactic/Rewrites.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModule.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModuleAllTest.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModuleMetaTest.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModuleNew.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModulePublicMetaTest.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModulePublicTest.lean,MathlibTest/Linter/DeprecatedModule/DeprecatedModuleTest.lean,MathlibTest/Linter/DeprecatedSyntaxLinter.lean,MathlibTest/Linter/DocPrime.lean,MathlibTest/Linter/DocString.lean,MathlibTest/Linter/EmptyLine.lean,MathlibTest/Linter/FlexibleLinter.lean,MathlibTest/Linter/ForbiddenModuleNames.lean,MathlibTest/Linter/HaveLetLinter.lean,MathlibTest/Linter/ImportHeavyFlexibleLinter.lean,MathlibTest/Linter/Lint.lean,MathlibTest/Linter/ModuleCasing.lean,MathlibTest/Linter/OldObtain.lean,MathlibTest/Linter/PrivateModuleLinter/HasOnlyPrivate.lean,MathlibTest/Linter/PrivateModuleLinter/HasPublic.lean,MathlibTest/Linter/PrivateModuleLinter/ImportOnly.lean,MathlibTest/Linter/PrivateModuleLinter/Initialize.lean,MathlibTest/Linter/PrivateModuleLinter/NonModule.lean,MathlibTest/Linter/PrivateModuleLinter/Notation3.lean,MathlibTest/Linter/PrivateModuleLinter/ReservedName1.lean,MathlibTest/Linter/PrivateModuleLinter/ReservedName2.lean,MathlibTest/Linter/Style/LintStyle.lean,MathlibTest/Linter/Style/LongFile.lean,MathlibTest/Linter/UnusedTactic/AesopUnusedTactic.lean,MathlibTest/Linter/UnusedTactic/UnusedTactic.lean,MathlibTest/Linter/ValidatePRTitle.lean,MathlibTest/Linter/VersoHeader.lean,MathlibTest/Linter/Whitespace.lean,MathlibTest/NormCast.lean,MathlibTest/RegisterTryTactic.lean,MathlibTest/RightActions.lean,MathlibTest/SetLike.lean,MathlibTest/SimpConfluence.lean,MathlibTest/SlimCheck.lean,MathlibTest/SlowInstances.lean,MathlibTest/SlowSimp.lean,MathlibTest/Tactic/ApplyCongr.lean,MathlibTest/Tactic/ApplyFun.lean,MathlibTest/Tactic/ApplyRules.lean,MathlibTest/Tactic/ApplyWith.lean,MathlibTest/Tactic/Bound/Attribute.lean,MathlibTest/Tactic/Bound/Bound.lean,MathlibTest/Tactic/ByContra.lean,MathlibTest/Tactic/CancelDenoms.lean,MathlibTest/Tactic/Cases.lean,MathlibTest/Tactic/CasesM.lean,MathlibTest/Tactic/Change.lean,MathlibTest/Tactic/Check.lean,MathlibTest/Tactic/Choose/Choose.lean,MathlibTest/Tactic/Choose/Reduction.lean,MathlibTest/Tactic/Clean.lean	192	5	['github-actions', 'grunweg', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	5-41090 5 days ago	5-41091 5 days ago	1-36847 1 day
35569	goliath-klein author:goliath-klein	refactor(PiTensorProduct/{InjectiveNorm, ProjectiveNorm}): deprecate `injectiveSeminorm`	This PR: * Deprecates `PiTensorProduct.injectiveSeminorm` and supporting lemmas. * Moves the theory of `liftEquiv` from InjectiveSeminorm.lean to ProjectiveSeminorm.lean. No changes are introduced beyond adding deprecation notices, adapting docstrings, and moving material between files. The PR leaves InjectiveSeminorm.lean almost empty. A new implementation of `injectiveSeminorm`, one which reflects the common mathematical definition, is to be done. This is the third in a series of three PRs with the goal to [deprecate `PiTensorProuduct.injectiveSeminorm`](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/injectiveSeminorm/with/568798633). --- - [ ] depends on: #35567 - [ ] depends on: #35568 Deprecations: - injectiveSeminorm - dualSeminorms_bounded - injectiveSeminorm_apply - norm_eval_le_injectiveSeminorm - injectiveSeminorm_le_projectiveSeminorm - injectiveSeminorm_tprod_le Preliminary work toward a reimplementation is at #33969. I've added Davood and myself to the "Authors" field, as we have now significantly refactored this module. Co-authored-by: Davood H. T. Tehrani [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict	222/233	Mathlib/Analysis/Normed/Module/PiTensorProduct/InjectiveSeminorm.lean,Mathlib/Analysis/Normed/Module/PiTensorProduct/ProjectiveSeminorm.lean	2	7	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	3-53122 3 days ago	3-53123 3 days ago	59-21262 59 days
36236	kim-em author:kim-em	chore: add module keyword to Archive and Counterexamples files	This PR converts 105 Archive and Counterexamples files to module format, adding `module`, `public import`, and `@[expose] public section`. Eight files are left unconverted for now: - Seven files containing `private` declarations that need further work (`Imo1962Q1`, `MiuLanguage/Basic`, `MiuLanguage/DecisionSuf`, `AscendingDescendingSequences`, `BallotProblem`, `AharoniKorman`, `TopologistsSineCurve`) - `Counterexamples/InvertibleModuleNotIdeal` which needs an import path update For `Archive/Examples/PropEncodable`, the `private` declarations were removed as part of this conversion. 🤖 Prepared with Claude Code	IMO LLM-generated merge-conflict	738/310	Archive/Arithcc.lean,Archive/Examples/Eisenstein.lean,Archive/Examples/Kuratowski.lean,Archive/Examples/PropEncodable.lean,Archive/Hairer.lean,Archive/Imo/Imo1959Q1.lean,Archive/Imo/Imo1959Q2.lean,Archive/Imo/Imo1960Q1.lean,Archive/Imo/Imo1960Q2.lean,Archive/Imo/Imo1961Q3.lean,Archive/Imo/Imo1962Q4.lean,Archive/Imo/Imo1963Q5.lean,Archive/Imo/Imo1964Q1.lean,Archive/Imo/Imo1969Q1.lean,Archive/Imo/Imo1972Q5.lean,Archive/Imo/Imo1975Q1.lean,Archive/Imo/Imo1977Q6.lean,Archive/Imo/Imo1981Q3.lean,Archive/Imo/Imo1982Q1.lean,Archive/Imo/Imo1985Q2.lean,Archive/Imo/Imo1986Q5.lean,Archive/Imo/Imo1987Q1.lean,Archive/Imo/Imo1988Q6.lean,Archive/Imo/Imo1994Q1.lean,Archive/Imo/Imo1997Q3.lean,Archive/Imo/Imo1998Q2.lean,Archive/Imo/Imo2001Q2.lean,Archive/Imo/Imo2001Q3.lean,Archive/Imo/Imo2001Q4.lean,Archive/Imo/Imo2001Q5.lean,Archive/Imo/Imo2001Q6.lean,Archive/Imo/Imo2002Q3.lean,Archive/Imo/Imo2005Q3.lean,Archive/Imo/Imo2005Q4.lean,Archive/Imo/Imo2006Q3.lean,Archive/Imo/Imo2006Q5.lean,Archive/Imo/Imo2008Q2.lean,Archive/Imo/Imo2008Q3.lean,Archive/Imo/Imo2008Q4.lean,Archive/Imo/Imo2010Q5.lean,Archive/Imo/Imo2011Q3.lean,Archive/Imo/Imo2011Q5.lean,Archive/Imo/Imo2013Q1.lean,Archive/Imo/Imo2013Q5.lean,Archive/Imo/Imo2015Q6.lean,Archive/Imo/Imo2019Q1.lean,Archive/Imo/Imo2019Q2.lean,Archive/Imo/Imo2019Q4.lean,Archive/Imo/Imo2020Q2.lean,Archive/Imo/Imo2021Q1.lean,Archive/Imo/Imo2024Q2.lean,Archive/Imo/Imo2024Q3.lean,Archive/Imo/Imo2024Q6.lean,Archive/Imo/Imo2025Q3.lean,Archive/Kuratowski.lean,Archive/MinimalSheffer.lean,Archive/OxfordInvariants/Summer2021/Week3P1.lean,Archive/Sensitivity.lean,Archive/Wiedijk100Theorems/AbelRuffini.lean,Archive/Wiedijk100Theorems/AreaOfACircle.lean,Archive/Wiedijk100Theorems/BirthdayProblem.lean,Archive/Wiedijk100Theorems/BuffonsNeedle.lean,Archive/Wiedijk100Theorems/CubingACube.lean,Archive/Wiedijk100Theorems/FriendshipGraphs.lean,Archive/Wiedijk100Theorems/HeronsFormula.lean,Archive/Wiedijk100Theorems/InverseTriangleSum.lean,Archive/Wiedijk100Theorems/Konigsberg.lean,Archive/Wiedijk100Theorems/PerfectNumbers.lean,Archive/Wiedijk100Theorems/SolutionOfCubicQuartic.lean,Archive/Wiedijk100Theorems/SumOfPrimeReciprocalsDiverges.lean,Archive/ZagierTwoSquares.lean,Counterexamples/CanonicallyOrderedCommSemiringTwoMul.lean,Counterexamples/CharPZeroNeCharZero.lean,Counterexamples/CliffordAlgebraNotInjective.lean,Counterexamples/Cyclotomic105.lean,Counterexamples/DimensionPolynomial.lean,Counterexamples/DirectSumIsInternal.lean,Counterexamples/DiscreteTopologyNonDiscreteUniformity.lean,Counterexamples/EulerSumOfPowers.lean,Counterexamples/Girard.lean,Counterexamples/HeawoodUnitDistance.lean,Counterexamples/HomogeneousPrimeNotPrime.lean,Counterexamples/IrrationalPowerOfIrrational.lean,Counterexamples/MapFloor.lean,Counterexamples/MonicNonRegular.lean,Counterexamples/Motzkin.lean,Counterexamples/NowhereDifferentiable.lean,Counterexamples/OrderedCancelAddCommMonoidWithBounds.lean,Counterexamples/PeanoCurve.lean,Counterexamples/Phillips.lean,Counterexamples/PolynomialIsDomain.lean,Counterexamples/Pseudoelement.lean,Counterexamples/QuadraticForm.lean,Counterexamples/SeminormLatticeNotDistrib.lean,Counterexamples/SeparableNotSecondCountable.lean,Counterexamples/SorgenfreyLine.lean,Counterexamples/ZeroDivisorsInAddMonoidAlgebras.lean	97	11	['JovanGerb', 'github-actions', 'grunweg', 'kim-em', 'mathlib-merge-conflicts']	dwrensha assignee:dwrensha	3-52993 3 days ago	3-52994 3 days ago	13-54332 13 days
38393	staroperator author:staroperator	refactor(ModelTheory): add typeclasses for algebraic symbols	`Language.ring` and `Language.presburger` share the same symbols `0`, `1` and `+` and have duplicated instances on `Term` and `realize` simp lemmas. This PR makes these symbols certain typeclasses (similar to [`Language.IsOrdered`](https://leanprover-community.github.io/mathlib4_docs/Mathlib/ModelTheory/Order.html#FirstOrder.Language.IsOrdered)) and removes the duplication. It also adds certain definability lemmas that `fun_prop` can use. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-logic merge-conflict	332/201	Mathlib.lean,Mathlib/ModelTheory/Algebra/Classes.lean,Mathlib/ModelTheory/Algebra/Field/IsAlgClosed.lean,Mathlib/ModelTheory/Algebra/Ring/Basic.lean,Mathlib/ModelTheory/Algebra/Ring/FreeCommRing.lean,Mathlib/ModelTheory/Arithmetic/Presburger/Basic.lean,Mathlib/ModelTheory/Arithmetic/Presburger/Definability.lean	7	2	['github-actions', 'mathlib-merge-conflicts']	fpvandoorn assignee:fpvandoorn	3-49194 3 days ago	3-49194 3 days ago	36-78490 36 days
39388	marcelolynch author:marcelolynch	chore: remove @[expose] from def-free public sections	Strip `@[expose]` from `public section` headers in 100 modules where no declaration needs its body visible downstream. A new sweep in the style of #38480 Found using the linter-in-progress: #39387 Relevant Zulip thread: https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Removing.20unnecessary.20.60.40.5Bexpose.5D.60/with/595180230	merge-conflict	100/100	Mathlib/Algebra/Category/Ring/Small.lean,Mathlib/Algebra/Field/Basic.lean,Mathlib/Algebra/Field/MinimalAxioms.lean,Mathlib/Algebra/Field/Opposite.lean,Mathlib/Algebra/Field/Rat.lean,Mathlib/Algebra/Field/ULift.lean,Mathlib/Algebra/Field/ZMod.lean,Mathlib/Algebra/Group/Action/Option.lean,Mathlib/Algebra/Group/Action/Sigma.lean,Mathlib/Algebra/Group/Action/Sum.lean,Mathlib/Algebra/Group/Action/Units.lean,Mathlib/Algebra/Group/Subgroup/Actions.lean,Mathlib/Algebra/Group/Submonoid/MulAction.lean,Mathlib/Algebra/Module/Projective.lean,Mathlib/Algebra/Module/Submodule/Basic.lean,Mathlib/Algebra/NonAssoc/LieAdmissible/Defs.lean,Mathlib/Algebra/Notation/Prod.lean,Mathlib/Algebra/Order/Floor/Div.lean,Mathlib/Algebra/Order/Group/Action/End.lean,Mathlib/Algebra/Order/Group/End.lean,Mathlib/Algebra/Order/Group/PosPart.lean,Mathlib/Algebra/Order/Kleene.lean,Mathlib/Algebra/Order/Nonneg/Lattice.lean,Mathlib/Algebra/Order/Pi.lean,Mathlib/Algebra/Order/Ring/Unbundled/Rat.lean,Mathlib/Algebra/Ring/Commute.lean,Mathlib/AlgebraicTopology/ModelCategory/Over.lean,Mathlib/Analysis/InnerProductSpace/Coalgebra.lean,Mathlib/Analysis/Normed/Algebra/TrivSqZeroExt.lean,Mathlib/Analysis/Normed/Group/Constructions.lean,Mathlib/Analysis/Normed/Module/MStructure.lean,Mathlib/Analysis/Normed/Operator/Compact/FiniteDimension.lean,Mathlib/Analysis/ODE/DiscreteGronwall.lean,Mathlib/CategoryTheory/Localization/DerivabilityStructure/OfLocalizedEquivalences.lean,Mathlib/CategoryTheory/MarkovCategory/Positive.lean,Mathlib/CategoryTheory/Monoidal/Cartesian/Normal.lean,Mathlib/CategoryTheory/Monoidal/Functor/Types.lean,Mathlib/CategoryTheory/Monoidal/Types/Coyoneda.lean,Mathlib/CategoryTheory/Sites/CoversTop/Over.lean,Mathlib/Combinatorics/Additive/FreimanHom.lean,Mathlib/Computability/AkraBazzi/AkraBazzi.lean,Mathlib/Data/ENNReal/Action.lean,Mathlib/Data/ENat/Pow.lean,Mathlib/Data/Finsupp/Pointwise.lean,Mathlib/Data/FunLike/Basic.lean,Mathlib/Data/FunLike/Embedding.lean,Mathlib/Data/FunLike/Equiv.lean,Mathlib/Data/Int/Cast/Pi.lean,Mathlib/Data/List/Monad.lean,Mathlib/Data/NNRat/Lemmas.lean,Mathlib/Data/Nat/Lattice.lean,Mathlib/Data/Prod/Lex.lean,Mathlib/Data/Rat/Cast/Defs.lean,Mathlib/Data/Rat/Cast/OfScientific.lean,Mathlib/Data/Real/Archimedean.lean,Mathlib/Data/ZMod/IntUnitsPower.lean,Mathlib/GroupTheory/GroupAction/Embedding.lean,Mathlib/GroupTheory/IsPerfect.lean,Mathlib/GroupTheory/ResiduallyFinite.lean,Mathlib/LinearAlgebra/CliffordAlgebra/Star.lean,Mathlib/LinearAlgebra/Projectivization/Action.lean,Mathlib/LinearAlgebra/RootSystem/GeckConstruction/Semisimple.lean,Mathlib/MeasureTheory/Function/L2Space.lean,Mathlib/MeasureTheory/Integral/IntegralEqImproper.lean,Mathlib/MeasureTheory/Measure/Sub.lean,Mathlib/MeasureTheory/Measure/Typeclasses/ZeroOne.lean,Mathlib/NumberTheory/ModularForms/EisensteinSeries/E2/Transform.lean,Mathlib/NumberTheory/NumberField/ExistsRamified.lean,Mathlib/NumberTheory/Padics/PadicVal/Defs.lean,Mathlib/Order/ConditionallyCompleteLattice/Basic.lean,Mathlib/Order/Filter/FilterProduct.lean,Mathlib/Order/Heyting/Basic.lean,Mathlib/Order/Interval/Set/OrdConnected.lean,Mathlib/Order/Quotient.lean,Mathlib/Probability/Kernel/Deterministic.lean,Mathlib/RingTheory/Coalgebra/Convolution.lean,Mathlib/RingTheory/Flat/IsBaseChange.lean,Mathlib/RingTheory/HopfAlgebra/TensorProduct.lean,Mathlib/RingTheory/Ideal/GoingDown.lean,Mathlib/RingTheory/Ideal/GoingUp.lean,Mathlib/RingTheory/Ideal/Maximal.lean,Mathlib/RingTheory/Localization/Finiteness.lean,Mathlib/RingTheory/Noetherian/Defs.lean,Mathlib/RingTheory/QuasiFinite/Basic.lean,Mathlib/RingTheory/QuasiFinite/Polynomial.lean,Mathlib/RingTheory/QuasiFinite/Weakly.lean,Mathlib/RingTheory/Regular/ProjectiveDimension.lean,Mathlib/RingTheory/SimpleModule/Basic.lean,Mathlib/RingTheory/Smooth/Fiber.lean,Mathlib/RingTheory/TensorProduct/IsBaseChangeRightExact.lean,Mathlib/RingTheory/Unramified/LocalRing.lean,Mathlib/RingTheory/Valuation/Extension.lean,Mathlib/RingTheory/Valuation/IsTrivialOn.lean,Mathlib/SetTheory/Cardinal/Regular.lean,Mathlib/Tactic/Algebra/Lemmas.lean,Mathlib/Topology/Algebra/UniformMulAction.lean,Mathlib/Topology/CWComplex/Classical/Subcomplex.lean,Mathlib/Topology/EMetricSpace/Pi.lean,Mathlib/Topology/List.lean,Mathlib/Topology/MetricSpace/Pseudo/Pi.lean	100	7	['eric-wieser', 'github-actions', 'grunweg', 'marcelolynch', 'mathlib-merge-conflicts', 'urkud']	nobody	3-48794 3 days ago	3-48795 3 days ago	15-20152 15 days
39449	Paul-Lez author:Paul-Lez	doc: add library note about scoping simp lemmas with weak keys	In PR #39262 I noticed that some `simp` lemmas were scoped for a reason that is not immediately obvious, so I figured that adding a library note would be nice in case anyone else runs into this in the future (this pattern is quite common in Mathlib!) In case it's helpful for review, here are links to a few of the PRs that added this scoping initially: - #14233 - #15620 - #15631 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict	71/4	Mathlib.lean,Mathlib/Algebra/AddConstMap/Basic.lean,Mathlib/Algebra/CharP/Two.lean,Mathlib/Algebra/GradedMonoid.lean,Mathlib/Algebra/Ring/BooleanRing.lean,Mathlib/Algebra/Ring/CharZero.lean,Mathlib/Tactic.lean,Mathlib/Tactic/SimpLibraryNote.lean	8	2	['github-actions', 'mathlib-merge-conflicts']	nobody	3-48663 3 days ago	3-48664 3 days ago	13-6519 13 days
39489	Paul-Lez author:Paul-Lez	fix: defeq abuse in HasFTaylorSeriesUpToOn.comp	Removes a `set_option backward.isDefEq.respectTransparency false`. The fix isn't as nice as I would have hoped (I tried to make it smaller but to no avail). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis merge-conflict	5/2	Mathlib/Analysis/Calculus/ContDiff/FaaDiBruno.lean	1	2	['github-actions', 'mathlib-merge-conflicts']	j-loreaux assignee:j-loreaux	3-48660 3 days ago	3-48660 3 days ago	12-81129 12 days
39582	plp127 author:plp127	chore: unsimp `Set.coe_setOf`	See [#mathlib4 > `Set.coe_setOf` @ 💬](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/.60Set.2Ecoe_setOf.60/near/579579409) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data merge-conflict	52/55	Archive/Imo/Imo1987Q1.lean,Mathlib/AlgebraicTopology/SimplicialSet/StdSimplex.lean,Mathlib/Analysis/SpecialFunctions/Trigonometric/Inverse.lean,Mathlib/CategoryTheory/GradedObject/Monoidal.lean,Mathlib/CategoryTheory/Sites/Coherent/RegularSheaves.lean,Mathlib/CategoryTheory/Sites/IsSheafFor.lean,Mathlib/CategoryTheory/Sites/Sieves.lean,Mathlib/Combinatorics/SimpleGraph/Connectivity/Finite.lean,Mathlib/Data/Set/Basic.lean,Mathlib/Data/Set/Finite/Lattice.lean,Mathlib/FieldTheory/SeparablyGenerated.lean,Mathlib/GroupTheory/Perm/Finite.lean,Mathlib/LinearAlgebra/RootSystem/OfBilinear.lean,Mathlib/NumberTheory/KummerDedekind.lean,Mathlib/RingTheory/DedekindDomain/Ideal/Lemmas.lean	15	2	['github-actions', 'mathlib-merge-conflicts']	nobody	3-48656 3 days ago	3-48657 3 days ago	6-13314 6 days
39773	kbuzzard author:kbuzzard	perf: add some fast_instance%	This PR adds some `fast_instance%`s, which tidies up some terms. See [#mathlib4 > fast_instance% plans](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/fast_instance.25.20plans/with/597402311) for explicit descriptions of what every change in this PR actually does to the terms in question. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra merge-conflict label:t-algebra$	6/4	Mathlib/Algebra/Group/Pi/Basic.lean,Mathlib/Algebra/Group/TypeTags/Basic.lean	2	4	['github-actions', 'kbuzzard', 'leanprover-radar', 'mathlib-merge-conflicts']	nobody	3-45132 3 days ago	3-45133 3 days ago	5-43152 5 days
39395	marcelolynch author:marcelolynch	chore(Tactic/Linter): reword PrivateLinter suggestion	This matches the granular-by-default philosophy of the new module system and produces files without superfluous `@[expose] public`, which we also want to flag as undesirable: we steer to making every @[expose] is per-decl and intentional, rather than section-wide Relevant Zulip thread: https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Removing.20unnecessary.20.60.40.5Bexpose.5D.60/with/595180230	t-linter merge-conflict	11/8	Mathlib/Tactic/Linter/PrivateModule.lean,MathlibTest/PrivateModuleLinter/hasOnlyPrivate.lean,MathlibTest/PrivateModuleLinter/notation3.lean,MathlibTest/PrivateModuleLinter/reservedName2.lean	4	4	['JovanGerb', 'github-actions', 'grunweg', 'marcelolynch', 'mathlib-merge-conflicts']	JovanGerb assignee:JovanGerb	2-85021 2 days ago	7-39674 7 days ago	11-15983 11 days
26413	michaellee94 author:michaellee94	feat: existence of maximal solutions for ODEs meeting Picard-Lindelöf conditions	Add existence proof for maximal solution of ODE using Picard-Lindelöf and a uniqueness theorem using Grönwall's lemma. --- - [x] depends on: #26382 - [x] depends on: #29186 - [ ] depends on: #35043 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-analysis merge-conflict	1300/431	Mathlib.lean,Mathlib/Analysis/ODE/Basic.lean,Mathlib/Analysis/ODE/ExistUnique.lean,Mathlib/Analysis/ODE/Gronwall.lean,Mathlib/Analysis/ODE/MaximalSolution.lean,Mathlib/Analysis/ODE/PicardLindelof.lean,Mathlib/Analysis/ODE/Transform.lean,Mathlib/Geometry/Manifold/IntegralCurve/Basic.lean,Mathlib/Geometry/Manifold/IntegralCurve/ExistUnique.lean,Mathlib/Geometry/Manifold/IntegralCurve/Transform.lean,Mathlib/Geometry/Manifold/IntegralCurve/UniformTime.lean,docs/1000.yaml,docs/undergrad.yaml	13	95	['botbaki-review', 'github-actions', 'grunweg', 'leanprover-community-bot-assistant', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'michaellee94', 'winstonyin']	nobody	2-58316 2 days ago	unknown	unknown
26394	winstonyin author:winstonyin	feat: existence of local flows on manifolds	This PR continues the work from #21777. Original PR: https://github.com/leanprover-community/mathlib4/pull/21777 Transfer the existence theorem of local flows on vector spaces to manifolds. The precise statement is: > If a vector field `v` on a manifold `M` is continuously differentiable at an interior point `x₀`, then for a given `t₀` there exists a neighbourhood `u` of `x₀`, a positive `ε`, and `γ : M → ℝ → M` such that `γ x` is an integral curve of `v` on `(t₀ - ε, t₀ + ε)` for all `x ∈ u`. This is powerful because all curves `γ x` (each with initial condition `x ∈ u`) share the same existence time interval `(t₀ - ε, t₀ + ε)`, rather than each curve having its own `ε`. This will allow us to show that $C^1$ vector fields on compact manifolds always have global integral curves / global flows. Any suggestions to shorten the proof or split out useful lemmas are welcome! - [x] depends on: #26392 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-differential-geometry merge-conflict	138/61	Mathlib/Analysis/ODE/PicardLindelof.lean,Mathlib/Geometry/Manifold/IntegralCurve/ExistUnique.lean,Mathlib/Order/Filter/Prod.lean	3	13	['github-actions', 'grunweg', 'leanprover-community-bot-assistant', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'ocfnash', 'winstonyin']	ocfnash assignee:ocfnash	2-57518 2 days ago	2-57519 2 days ago	23-1300 23 days
37680	IvanRenison author:IvanRenison	feat(Combinatorics/SimpleGraph/Clique): add lemmas about isomorphisms and cliques	--- Idea from this Zulip thread: [#graph theory>Second Order Monadic Logic for Graph ](https://leanprover.zulipchat.com/#narrow/channel/252551-graph-theory/topic/Second.20Order.20Monadic.20Logic.20for.20Graph/with/583013775) - [x] depends on: #37649 - [x] depends on: #37640 - [x] depends on: #37676 - [ ] depends on: #37697 - [ ] depends on: #37700 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics merge-conflict	156/0	Mathlib/Combinatorics/SimpleGraph/Clique.lean,Mathlib/Combinatorics/SimpleGraph/Maps.lean	2	6	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	0-69943 19 hours ago	unknown	unknown
36165	Parcly-Taxel author:Parcly-Taxel	chore: deprecate `Nat.strongRec(On)'`	In favour of Batteries's `Nat.strongRec` for definitions and `Nat.strong_induction_on` for proofs.	t-data merge-conflict	34/66	Mathlib/Analysis/Analytic/Inverse.lean,Mathlib/Data/Int/GCD.lean,Mathlib/Data/Nat/Factorization/Induction.lean,Mathlib/Data/Nat/Init.lean,Mathlib/Data/Set/Finite/Basic.lean,Mathlib/Data/ZMod/Basic.lean,Mathlib/GroupTheory/SpecificGroups/Cyclic.lean,Mathlib/Topology/EMetricSpace/Paracompact.lean	8	7	['JovanGerb', 'MichaelStollBayreuth', 'Parcly-Taxel', 'Vierkantor', 'github-actions', 'mathlib-bors', 'mathlib-merge-conflicts']	Vierkantor assignee:Vierkantor	0-1417 23 minutes ago	73-79537 73 days ago	15-50927 15 days

Stale new contributor PRs

Number	Author	Title	Description	Labels	+/-	Modified files (first 100)	📝	💬	All users who commented or reviewed	Assignee(s)	Updated	Last status change	total time in review
14563	awueth author:awueth	feat: if-then-else of exclusive or statement	--- If `¬(P ∧ Q)` then `ite (P ∨ Q) a 1 = (ite P a 1) * (ite Q a 1)` [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-algebra new-contributor label:t-algebra$	5/0	Mathlib/Algebra/Group/Basic.lean	1	3	['eric-wieser', 'github-actions', 'kim-em']	nobody	656-16503 1 year ago	unknown	unknown
12751	Command-Master author:Command-Master	feat: add lemmas for Nat/Bits, Nat/Bitwise and Nat/Size	Remove `@[simp]` from `Nat.bit_false` and `Nat.bit_true`, as `bit0` and `bit1` are deprecated, and add some lemmas to `Bits`, `Bitwise` and `Size`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-data new-contributor	66/7	Mathlib/Data/Nat/Bits.lean,Mathlib/Data/Nat/Bitwise.lean,Mathlib/Data/Nat/Multiplicity.lean,Mathlib/Data/Nat/Size.lean	4	26	['Command-Master', 'Rida-Hamadani', 'Ruben-VandeVelde', 'YaelDillies', 'github-actions', 'jcommelin']	nobody	652-1412 1 year ago	unknown	unknown
14669	Command-Master author:Command-Master	feat(Data/Nat/PartENat): add lemmas for PartENat	Add some missing lemmas for `PartENat`, as well as the additive homomorphism from it to `WithTop Int`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-data new-contributor merge-conflict	90/0	Mathlib/Data/Nat/PartENat.lean	1	4	['erdOne', 'github-actions', 'mathlib-merge-conflicts', 'urkud']	nobody	639-13302 1 year ago	unknown	unknown
15121	Eloitor author:Eloitor	feat: iff theorems for IsSplitEpi and IsSplitMono in opposite category	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-category-theory new-contributor	40/0	Mathlib/CategoryTheory/EpiMono.lean	1	3	['github-actions', 'joelriou', 'mattrobball']	nobody	638-62647 1 year ago	unknown	unknown
14242	js2357 author:js2357	feat: Prove equivalence of `isDedekindDomain` and `isDedekindDomainDvr`	Prove that `isDedekindDomainDvr` is equivalent to both `isDedekindDomain` and `isDedekindDomainInv`. Specifically, prove `isDedekindDomainDvr A → isDedekindDomainInv A`, because `isDedekindDomain A → isDedekindDomainDvr A` and `IsDedekindDomain A ↔ IsDedekindDomainInv A` are already in Mathlib. - [x] depends on: #14099 - [x] depends on: #14216 - [ ] depends on: #14237 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebra blocked-by-other-PR new-contributor label:t-algebra$	269/1	Mathlib.lean,Mathlib/RingTheory/DedekindDomain/Dvr.lean,Mathlib/RingTheory/FractionalIdeal/LocalizedAtPrime.lean,Mathlib/RingTheory/Localization/Basic.lean	4	2	['github-actions', 'leanprover-community-mathlib4-bot']	nobody	615-73706 1 year ago	unknown	unknown
16887	metinersin author:metinersin	feat(ModelTheory/Complexity): define conjunctive and disjunctive formulas	Defines `FirstOrder.Language.BoundedFormula.IsConjunctive` and `FirstOrder.Language.BoundedFormula.IsDisjunctive`. --- - [ ] depends on: #16885 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR new-contributor t-logic	300/7	Mathlib/ModelTheory/Complexity.lean,Mathlib/ModelTheory/Equivalence.lean,Mathlib/ModelTheory/Syntax.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	607-69684 1 year ago	unknown	unknown
16888	metinersin author:metinersin	feat(ModelTheory/Complexity): Define conjunctive and disjunctive normal forms	Define `FirstOrder.Language.BoundedFormula.IsDNF` and `FirstOrder.Language.BoundedFormula.IsCNF`. --- - [ ] depends on: #16887 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR new-contributor t-logic	415/7	Mathlib/ModelTheory/Complexity.lean,Mathlib/ModelTheory/Equivalence.lean,Mathlib/ModelTheory/Syntax.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	607-69684 1 year ago	unknown	unknown
16889	metinersin author:metinersin	feat(ModelTheory/Complexity): Normal forms	Defines `FirstOrder.Language.BoundedFormula.toDNF` and `FirstOrder.Language.BoundedFormula.toCNF` - given a quantifier-free formula, these construct a semantically equivalent formula in disjunctive normal form and conjunctive normal form, respectively. --- - [ ] depends on: #16888 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR new-contributor t-logic	525/7	Mathlib/ModelTheory/Complexity.lean,Mathlib/ModelTheory/Equivalence.lean,Mathlib/ModelTheory/Syntax.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	607-69683 1 year ago	unknown	unknown
14619	Command-Master author:Command-Master	chore: Merge `Trunc` to `Squash`	Remove `Trunc` and use `Squash` instead --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP new-contributor	197/211	Mathlib/CategoryTheory/EpiMono.lean,Mathlib/CategoryTheory/Preadditive/Biproducts.lean,Mathlib/Data/DFinsupp/Basic.lean,Mathlib/Data/Fintype/Basic.lean,Mathlib/Data/Fintype/Card.lean,Mathlib/Data/Fintype/Option.lean,Mathlib/Data/Fintype/Perm.lean,Mathlib/Data/Fintype/Quotient.lean,Mathlib/Data/Quot.lean,Mathlib/Data/Semiquot.lean,Mathlib/GroupTheory/Perm/Cycle/Factors.lean,Mathlib/GroupTheory/Perm/Sign.lean,Mathlib/Logic/Equiv/List.lean	13	3	['Command-Master', 'github-actions', 'vihdzp']	nobody	598-29834 1 year ago	unknown	unknown
12750	Command-Master author:Command-Master	feat: define Gray code	--- Define binary reflected gray code, both as a permutation of `Nat` and as a permutation of `BitVec n`, and prove some theorems about them. Additionally, remove `@[simp]` from `Nat.bit_false` and `Nat.bit_true`, as `bit0` and `bit1` are deprecated, and add some lemmas to `Bits`, `Bitwise` and `Size`. - [ ] depends on: #12751 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	blocked-by-other-PR t-data new-contributor merge-conflict awaiting-author	226/0	Mathlib.lean,Mathlib/Data/Nat/Bits.lean,Mathlib/Data/Nat/Bitwise.lean,Mathlib/Data/Nat/GrayCode.lean,Mathlib/Data/Nat/Size.lean	5	5	['Rida-Hamadani', 'alreadydone', 'github-actions', 'grunweg', 'leanprover-community-mathlib4-bot']	nobody	590-5941 1 year ago	unknown	unknown
14598	Command-Master author:Command-Master	chore: add typeclasses to unify various `add_top`, `add_eq_top`, etc.	Add the four typeclasses `IsTopAbsorbing`, `IsBotAbsorbing`, `NoTopSum`, `NoBotSum`, as additive equivalents for `MulZeroClass` and `NoZeroDivisors`. Add instances of these for `ENNReal`, `WithTop α`, `WithBot α`, `PUnit`, `EReal`, `PartENat`, `Measure`, `Interval` and `Filter`. Also split `Algebra/Order/AddGroupWithTop` to `Algebra/Order/Group/WithTop` and `Algebra/Order/Monoid/WithTop` --- Previous usages of lemmas with quantified names like `WithTop.add_top` have to be changed to just `add_top`. `add_lt_top` is `@[simp]`, in accordance with `ENNReal.add_lt_top` being `@[simp]`. This affects `WithTop.add_lt_top` which previously hadn't been `@[simp]`. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebra t-order new-contributor label:t-algebra$	264/195	Archive/Wiedijk100Theorems/BallotProblem.lean,Mathlib.lean,Mathlib/Algebra/Order/Group/WithTop.lean,Mathlib/Algebra/Order/GroupWithZero/Canonical.lean,Mathlib/Algebra/Order/Interval/Basic.lean,Mathlib/Algebra/Order/Monoid/Unbundled/Basic.lean,Mathlib/Algebra/Order/Monoid/Unbundled/Defs.lean,Mathlib/Algebra/Order/Monoid/Unbundled/WithTop.lean,Mathlib/Algebra/Order/Monoid/WithTop.lean,Mathlib/Algebra/PUnitInstances/Order.lean,Mathlib/Algebra/Polynomial/Degree/Definitions.lean,Mathlib/Algebra/Polynomial/Monic.lean,Mathlib/Algebra/Tropical/Basic.lean,Mathlib/Analysis/Analytic/Meromorphic.lean,Mathlib/Analysis/Normed/Lp/ProdLp.lean,Mathlib/Analysis/NormedSpace/ENorm.lean,Mathlib/Analysis/SpecialFunctions/JapaneseBracket.lean,Mathlib/Analysis/SpecialFunctions/Log/ENNRealLog.lean,Mathlib/Data/ENNReal/Operations.lean,Mathlib/Data/ENat/Basic.lean,Mathlib/Data/Nat/PartENat.lean,Mathlib/Data/Nat/WithBot.lean,Mathlib/Data/Real/EReal.lean,Mathlib/LinearAlgebra/Lagrange.lean,Mathlib/MeasureTheory/Covering/Differentiation.lean,Mathlib/MeasureTheory/Decomposition/Lebesgue.lean,Mathlib/MeasureTheory/Function/ConditionalExpectation/CondexpL1.lean,Mathlib/MeasureTheory/Function/Jacobian.lean,Mathlib/MeasureTheory/Function/L1Space.lean,Mathlib/MeasureTheory/Function/L2Space.lean,Mathlib/MeasureTheory/Function/LpSeminorm/Basic.lean,Mathlib/MeasureTheory/Function/LpSeminorm/TriangleInequality.lean,Mathlib/MeasureTheory/Function/LpSpace.lean,Mathlib/MeasureTheory/Function/StronglyMeasurable/Basic.lean,Mathlib/MeasureTheory/Function/UniformIntegrable.lean,Mathlib/MeasureTheory/Integral/Bochner.lean,Mathlib/MeasureTheory/Integral/MeanInequalities.lean,Mathlib/MeasureTheory/Integral/SetIntegral.lean,Mathlib/MeasureTheory/Integral/VitaliCaratheodory.lean,Mathlib/MeasureTheory/Measure/Hausdorff.lean,Mathlib/MeasureTheory/Measure/Lebesgue/Basic.lean,Mathlib/MeasureTheory/Measure/LevyProkhorovMetric.lean,Mathlib/MeasureTheory/Measure/MeasureSpace.lean,Mathlib/MeasureTheory/Measure/MeasureSpaceDef.lean,Mathlib/MeasureTheory/Measure/Regular.lean,Mathlib/MeasureTheory/Measure/Typeclasses.lean,Mathlib/NumberTheory/Padics/PadicNumbers.lean,Mathlib/Order/Filter/Pointwise.lean,Mathlib/Probability/Kernel/Defs.lean,Mathlib/Probability/Martingale/Convergence.lean,Mathlib/RingTheory/Multiplicity.lean,Mathlib/RingTheory/MvPowerSeries/NoZeroDivisors.lean,Mathlib/RingTheory/UniqueFactorizationDomain.lean,Mathlib/Topology/EMetricSpace/Defs.lean,Mathlib/Topology/MetricSpace/Bounded.lean,Mathlib/Topology/MetricSpace/HausdorffDistance.lean,Mathlib/Topology/MetricSpace/Lipschitz.lean	57	30	['Command-Master', 'YaelDillies', 'github-actions']	nobody	573-34217 1 year ago	unknown	unknown
16885	metinersin author:metinersin	feat(ModelTheory/Complexity): define literals	Defines `FirstOrder.Language.BoundedFormula.IsLiteral` and `FirstOrder.Language.BoundedFormula.simpleNot` - an auxiliary operation that takes the negation of a formula and does some simplification. --- - [x] depends on: #16800 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author new-contributor t-logic	148/5	Mathlib/ModelTheory/Complexity.lean,Mathlib/ModelTheory/Equivalence.lean,Mathlib/ModelTheory/Semantics.lean,Mathlib/ModelTheory/Syntax.lean	4	20	['YaelDillies', 'awainverse', 'github-actions', 'mathlib4-dependent-issues-bot', 'metinersin']	nobody	570-76738 1 year ago	unknown	unknown
13248	hcWang942 author:hcWang942	feat: basic concepts of auction theory	## Description Formalise some core concepts and results in auction theory: this includes definitions for first-price and second-price auctions, as well as several fundamental results and helping lemmas. This is the very first PR of the project formalizing core concepts and results in auction theory. Our group is working on more contributions on the formalization of game theory prefix. Co-authored-by: Ma Jiajun ## Reference Roughgarden, Tim. *Twenty Lectures on Algorithmic Game Theory*. Cambridge University Press, 2020. [Link](https://www.cambridge.org/core/books/twenty-lectures-on-algorithmic-game-theory/A9D9427C8F43E7DAEF8C702755B6D72B) --- - [x] Will depend on #14163 once that PR is merged. The Fintype lemmas introduced by this PR have been added in that PR and will be removed from here once that PR gets merged ## Current plan for formalization of Game Theory The current plan for the formalizing of Game Theory include: #### 1. Auction Theory. 🎉 _(200+ lines, this PR)_ - Essential definitions of Sealed-bid auction, First-price auction and Second-price auction. - First-price auction has no dominant strategy. - Second-price auction has dominant strategy. (Second-price auction is DSIC) #### 2. Mechanism design & Myerson's Lemma. 🎉 (400+ lines, pending for modification to Mathlib Standard) - Mechanism design An allocation rule is implementable if there exists - Dominant Strategy Incentive Compatible (DSIC) payment rule - An allocation rule is monotone if for every bidder’s gain is nondecreasing w.r.t. her/his bid - Myerson's Lemma Implementable ⇔ Monotone In the above case, the DSIC payment rule is unique. #### 3. von Neumann‘s Minimax Theorem. 🎉 (800+ lines, pending for modification to Mathlib Standard) - Equilibrium in zero sum game - Formalization strategy: via Loomis’s theorem. #### 4. Nash Equilibrium. 🎉 (pending for modification to Mathlib Standard) #### 5. Brouwer fixed-point theorem. (Work in Progress) #### 6. More Mechanism design. (Planning)	merge-conflict awaiting-author new-contributor t-logic	204/0	Mathlib.lean,Mathlib/GameTheory/Auction/Basic.lean,docs/references.bib	3	148	['Shreyas4991', 'YaelDillies', 'eric-wieser', 'faenuccio', 'github-actions', 'grunweg', 'hcWang942', 'tb65536', 'urkud', 'vihdzp']	hcWang942 assignee:hcWang942	566-29170 1 year ago	unknown	unknown
19125	yhtq author:yhtq	feat: add theorems to transfer `IsGalois` between pairs of fraction rings	feat: add theorems to transfer `IsGalois` between pairs of fraction rings. - [x] depends on: #18404 - [x] depends on: #19124 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebra new-contributor label:t-algebra$	121/0	Mathlib.lean,Mathlib/FieldTheory/Galois/IsFractionRing.lean,Mathlib/RingTheory/Localization/FractionRing.lean	3	3	['github-actions', 'mathlib4-dependent-issues-bot', 'tb65536']	nobody	536-51587 1 year ago	unknown	unknown
17739	Aaron1011 author:Aaron1011	feat(Topology/Order/DenselyOrdered): prove Not (IsOpen) for intervals	Prove that Iic/Ici/Ioc/Ico/Icc intervals are not open in densely ordered topologies with no min/max element --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-topology new-contributor	27/0	Mathlib/Topology/Order/DenselyOrdered.lean	1	8	['github-actions', 'vihdzp']	nobody	502-73599 1 year ago	unknown	unknown
15711	znssong author:znssong	feat(Combinatorics/SimpleGraph): Some lemmas about walk, cycle and Hamiltonian cycle	--- These lemmas are separated from the `meow-sister/BondyChvatal` branch and will be needed for the proof of the Bondy-Chvátal theorem. - [x] depends on: #15536 - [x] depends on: #16294	merge-conflict awaiting-author t-combinatorics new-contributor	407/3	Mathlib/Combinatorics/SimpleGraph/Finite.lean,Mathlib/Combinatorics/SimpleGraph/Hamiltonian.lean,Mathlib/Combinatorics/SimpleGraph/Path.lean,Mathlib/Combinatorics/SimpleGraph/Walk.lean	4	22	['Rida-Hamadani', 'YaelDillies', 'github-actions', 'mathlib4-dependent-issues-bot', 'znssong']	nobody	502-6285 1 year ago	unknown	unknown
15720	znssong author:znssong	feat(SimpleGraph): The Bondy-Chvátal theorem	The proof of the Bondy-Chvátal theorem, with Dirac's theorem and Ore's theorem as its corollary. - [x] depends on: #15536 - [ ] depends on: #15711 - [ ] depends on: #15578	merge-conflict blocked-by-other-PR t-combinatorics new-contributor	903/3	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/BondyChvatal.lean,Mathlib/Combinatorics/SimpleGraph/Finite.lean,Mathlib/Combinatorics/SimpleGraph/Hamiltonian.lean,Mathlib/Combinatorics/SimpleGraph/Path.lean,Mathlib/Combinatorics/SimpleGraph/Walk.lean,Mathlib/Dynamics/FixedPoints/Basic.lean,Mathlib/Dynamics/FixedPoints/Increasing.lean	8	3	['github-actions', 'grunweg']	nobody	502-6285 1 year ago	unknown	unknown
18629	tomaz1502 author:tomaz1502	feat(Computability.Timed): Formalization of runtime complexity of List.merge	This PR adds the formalization of the runtime complexity of the merge function, defined in `Data/List/Sort`. Requires: https://github.com/leanprover-community/mathlib4/pull/15450 References: - Previous PR on mathlib3: https://github.com/leanprover-community/mathlib3/pull/14494/ - First discussion on Zulip: https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/BSc.20Final.20Project/near/220647062 - Second disussion on Zulip: https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Formalization.20of.20Runtime.20Complexity.20of.20Sorting.20Algorithms/near/284184450 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-computability awaiting-author new-contributor	186/0	Mathlib.lean,Mathlib/Computability/Timed/InsertionSort.lean,Mathlib/Computability/Timed/Merge.lean	3	2	['github-actions', 'trivial1711']	nobody	501-58604 1 year ago	unknown	unknown
18461	hannahfechtner author:hannahfechtner	feat: left and right common multiples mixins	add mixins for left and right common multiples. These carry the data of what factors are used to create the common multiples --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-algebra new-contributor label:t-algebra$	78/0	Mathlib/Algebra/Group/Defs.lean	1	13	['github-actions', 'hannahfechtner', 'jcommelin', 'kbuzzard', 'kim-em', 'trivial1711']	nobody	498-19784 1 year ago	unknown	unknown
19291	PieterCuijpers author:PieterCuijpers	feat(Algebra/Order/Hom): add quantale homomorphism	Definition of quantale homomorphisms as functions that are both semigroup homomorphisms and complete lattice homomorphisms. --- - [x] depends on: #19810 - [x] depends on: #19811 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-algebra new-contributor label:t-algebra$	209/0	Mathlib.lean,Mathlib/Algebra/Order/Hom/Quantale.lean,scripts/noshake.json	3	29	['PieterCuijpers', 'YaelDillies', 'github-actions', 'kim-em', 'mathlib4-dependent-issues-bot']	nobody	496-80263 1 year ago	unknown	unknown
20372	jvlmdr author:jvlmdr	feat(MeasureTheory/Function): Add ContinuousLinearMap.bilinearCompLp(L)	Introduce ContinuousLinearMap.bilinearCompLp and bilinearCompLpL. Generalize eLpNorm_le_eLpNorm_mul_eLpNorm theorems to include constant C in bound condition. --- Expect this may be useful for defining tempered distributions from functions in `L^p`. The definitions more or less follow `ContinuousLinearMap.compLp...`. Names are loosely analogous to `ContinuousLinearMap.bilinearComp` and `SchwartzMap.bilinLeftCLM`. Note: I preferred the spelling `hpqr : p⁻¹ + q⁻¹ = r⁻¹` with `f` in `L^p` and `g` in `L^q` to `hpqr : 1 / p = 1 / q + 1 / r`. It's easier to obtain from `ENNReal.IsConjExponent` too. A few questions: - [ ] I defined `bilinear{Left,Right}LpL` in addition to `bilinearCompLpL` because `LinearMap.mkContinuous₂` is marked as `noncomputable` and `LinearMap.mkContinuous` is not. Is this worth the extra definitions? (Note: This is not visible in the source due to `noncomputable section`.) - [ ] Should I use `C : ℝ` instead of `C : NNReal` for `eLpNorm_le_eLpNorm_mul_eLpNorm'_of_norm'`? - [ ] Is it going to be painful to have `[Fact (1 ≤ p)] [Fact (1 ≤ q)] [Fact (1 ≤ r)]`? I don't think there's a way to avoid it though. Maybe providing specialized versions for `p.IsConjExponent q` with `L^1`? Naming: - [ ] Is it satisfactory to add a `'` to the `eLpNorm_le_eLpNorm_mul_eLpNorm ` definitions in `CompareExp.lean` where `≤ ‖f x‖ * ‖g x‖` has been replaced with `≤ C * ‖f x‖ * ‖g x‖`? These could replace the existing theorems, although I don't want to break backwards compatibility. There are 5 instances: `eLpNorm_le_eLpNorm_top_mul_eLpNorm'`, `eLpNorm_le_eLpNorm_mul_eLpNorm_top'`, `eLpNorm'_le_eLpNorm'_mul_eLpNorm''`, `eLpNorm_le_eLpNorm_mul_eLpNorm_of_nnnorm'`, `eLpNorm_le_eLpNorm_mul_eLpNorm'_of_norm'` (I'm not sure why the existing theorem `eLpNorm_le_eLpNorm_mul_eLpNorm'_of_norm` has an internal `'`) - [ ] Is `bilinearLeftLpL` a suitable name? Other options: `bilinearCompLpLeftL`, `bilinearCompLeftLpL`, `bilinLeftLpL` (analogous to `SchwartzMap.bilinLeftCLM`) [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-measure-probability new-contributor	203/40	Mathlib/MeasureTheory/Function/LpSeminorm/CompareExp.lean,Mathlib/MeasureTheory/Function/LpSpace.lean	2	1	['github-actions']	nobody	490-11211 1 year ago	unknown	unknown
20248	peabrainiac author:peabrainiac	feat(Topology/Compactness): first-countable locally path-connected spaces are delta-generated	Shows that all first-countable locally path-connected spaces are delta-generated (so in particular all normed spaces and convex subsets thereof are), and that delta-generated spaces are equivalently generated by the unit interval or standard simplices. --- - [ ] depends on: #21616 In principle, this should be close to all that's required to show that all simplicial complexes and CW-complexes are delta-generated; I just haven't done it yet because I'm not sure which file to best do it in. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	blocked-by-other-PR large-import new-contributor merge-conflict awaiting-author t-topology	1189/813	Mathlib.lean,Mathlib/Geometry/Manifold/ChartedSpace.lean,Mathlib/Topology/Algebra/Module/LocallyConvex.lean,Mathlib/Topology/Compactness/DeltaGeneratedSpace.lean,Mathlib/Topology/Connected/LocPathConnected.lean,Mathlib/Topology/Connected/PathConnected.lean,Mathlib/Topology/ContinuousOn.lean,Mathlib/Topology/Homotopy/HSpaces.lean,Mathlib/Topology/Path.lean	9	22	['YaelDillies', 'github-actions', 'kbuzzard', 'mathlib4-dependent-issues-bot', 'peabrainiac']	nobody	477-54921 1 year ago	unknown	unknown
19943	AlexLoitzl author:AlexLoitzl	feat(Computability): Add Chomsky Normal Form Grammar and translation	- Define Chomsky normal form grammars - Add language-preserving translation between context-free grammars and Chomsky normal form grammars Co-authored-by: Martin Dvorak martin.dvorak@matfyz.cz --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-computability awaiting-author new-contributor	3151/0	Mathlib.lean,Mathlib/Computability/ChomskyNormalForm/Basic.lean,Mathlib/Computability/ChomskyNormalForm/EmptyElimination.lean,Mathlib/Computability/ChomskyNormalForm/LengthRestriction.lean,Mathlib/Computability/ChomskyNormalForm/TerminalRestriction.lean,Mathlib/Computability/ChomskyNormalForm/Translation.lean,Mathlib/Computability/ChomskyNormalForm/UnitElimination.lean,Mathlib/Computability/ContextFreeGrammar.lean	8	59	['AlexLoitzl', 'YaelDillies', 'github-actions', 'kim-em', 'madvorak']	nobody	473-2620 1 year ago	unknown	unknown
21501	sksgurdldi author:sksgurdldi	feat(List): add sum_zipWith_eq_finset_sum	### Description: This PR adds the lemma `List.sum_zipWith_eq_finset_sum` to `Mathlib.Algebra.BigOperators.Group.Finset.Basic`. #### Statement: The sum of the `zipWith` operation on two lists equals the sum of applying the operation to corresponding elements of the two lists, indexed over the minimum of their lengths. #### Formal Statement: ```lean lemma sum_zipWith_eq_finset_sum [Inhabited α] [Inhabited β] [AddCommMonoid γ] {op : α → β → γ} (l : List α) (m : List β) : (List.zipWith op l m).sum = ∑ x ∈ (Finset.range (Nat.min l.length m.length)), op (l[x]!) (m[x]!) ``` #### Remarks: - This lemma provides a useful equivalence between `List.zipWith` and summation over a `Finset.range` indexed by `Nat.min l.length m.length`. - It can be helpful in algebraic manipulations involving list-based summations. #### Dependencies: No additional dependencies. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-algebra new-contributor label:t-algebra$	43/0	Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean	1	1	['github-actions', 'j-loreaux']	nobody	467-57791 1 year ago	unknown	unknown
21959	BGuillemet author:BGuillemet	feat(Topology/ContinuousMap): Stone-Weierstrass theorem for MvPolynomial	Add the subalgebra of multivariate polynomials and prove it separates points, on the same model as `ContinuousMap/Polynomial.lean`. Prove the Stone-Weierstrass theorem and some variations for multivariate polynomials. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-topology new-contributor	285/1	Mathlib.lean,Mathlib/Topology/ContinuousMap/MvPolynomial.lean,Mathlib/Topology/ContinuousMap/StoneWeierstrass.lean	3	1	['github-actions']	nobody	453-83632 1 year ago	unknown	unknown
15578	znssong author:znssong	feat(Function): Fixed points of function `f` with `f(x) >= x`	We added some lemmas of fixed points of function `f` with `f(x) >= x`, where `f : α → α` is a function on a finite type `α`. This will be needed in proof of Bondy-Chvátal theorem. --- See also branch `meow-sister/BondyChvatal`. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-analysis new-contributor	82/0	Mathlib.lean,Mathlib/Dynamics/FixedPoints/Basic.lean,Mathlib/Dynamics/FixedPoints/Increasing.lean	3	32	['Ruben-VandeVelde', 'YaelDillies', 'github-actions', 'urkud', 'vihdzp', 'znssong']	nobody	445-79458 1 year ago	unknown	unknown
21018	markimunro author:markimunro	feat(Data/Matrix): add file with key definitions and theorems about elementary row operations	Prove that each elementary row operation is equivalent to a multiplication by an elementary matrix, has another row operation which inverts it, and that each elementary matrix has a left inverse. This is a very large PR and I understand it will take time. This is my first one and will likely have issues but I will be ready to answer questions/fix them as soon as possible. Co-authored-by: Christopher Lynch --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data enhancement new-contributor merge-conflict awaiting-author	1230/0	Mathlib.lean,Mathlib/Data/Matrix/ElementaryRowOperations.lean,Mathlib/Data/Matrix/GaussianElimination.lean,Mathlib/Data/Matrix/GaussianEliminationOld,Mathlib/Data/Matrix/oldnames,et --hard 18533caba32,lean-toolchain	7	17	['chrisflav', 'eric-wieser', 'github-actions', 'j-loreaux', 'markimunro']	nobody	427-28457 1 year ago	unknown	unknown
15212	victorliu5296 author:victorliu5296	feat: Add fundamental theorem of calculus-2 for Banach spaces	add the Mean Value Theorem for Banach spaces to the library and include reference for the theorem statement This theorem states that if `f : X → Y` is differentiable along the line segment from `a` to `b`, then the change in `f` equals the integral of its derivative along this path. This extends the mean value theorem to Banach spaces. This can be used for the eventual proof of the Newton-Kantorovich theorem with 1 constant contained inside the added reference. Here is the discussion on Zulipchat: https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/Contributing.20FTC-2.20for.20Banach.20spaces	t-measure-probability new-contributor merge-conflict awaiting-author t-analysis	60/1	Mathlib/MeasureTheory/Integral/FundThmCalculus.lean	1	3	['github-actions', 'hrmacbeth', 'victorliu5296']	nobody	422-23446 1 year ago	unknown	unknown
22308	plp127 author:plp127	feat (Analysis/Convex): Generalize `Convex` lemmas to `StarConvex`	This PR generalizes many lemmas assuming `Convex 𝕜 s` to assume `StarConvex 𝕜 0 s`. --- - [x] depends on: #22421 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP t-analysis new-contributor	30/18	Mathlib/Analysis/Convex/Gauge.lean,Mathlib/Analysis/Convex/GaugeRescale.lean,Mathlib/Analysis/Convex/Star.lean,Mathlib/Analysis/LocallyConvex/AbsConvexOpen.lean	4	5	['Paul-Lez', 'github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot']	nobody	419-9366 1 year ago	unknown	unknown
21488	imbrem author:imbrem	feat(CategoryTheory/Monoidal): premonoidal categories	Add support for premonoidal categories --- Still want to add support for: - Premonoidal braided/symmetric categories - The monoidal coherence theorem, which I've already ported in my `discretion` library - The `coherence` tactic, which should work fine for premonoidal categories too but wanted to get this in front of reviewers ASAP to make sure my general approach was alright [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-category-theory new-contributor	900/361	Mathlib/Algebra/Category/ModuleCat/Presheaf/Monoidal.lean,Mathlib/CategoryTheory/Bicategory/End.lean,Mathlib/CategoryTheory/GradedObject/Monoidal.lean,Mathlib/CategoryTheory/Localization/Monoidal.lean,Mathlib/CategoryTheory/Monoidal/Braided/Basic.lean,Mathlib/CategoryTheory/Monoidal/Category.lean,Mathlib/CategoryTheory/Monoidal/Center.lean,Mathlib/CategoryTheory/Monoidal/CoherenceLemmas.lean,Mathlib/CategoryTheory/Monoidal/Discrete.lean,Mathlib/CategoryTheory/Monoidal/End.lean,Mathlib/CategoryTheory/Monoidal/Free/Basic.lean,Mathlib/CategoryTheory/Monoidal/Functor.lean,Mathlib/CategoryTheory/Monoidal/FunctorCategory.lean,Mathlib/CategoryTheory/Monoidal/Mon_.lean,Mathlib/CategoryTheory/Monoidal/Opposite.lean,Mathlib/CategoryTheory/Monoidal/Transport.lean,Mathlib/Tactic/CategoryTheory/Monoidal/Datatypes.lean,Mathlib/Tactic/CategoryTheory/Monoidal/Normalize.lean,Mathlib/Tactic/CategoryTheory/Monoidal/PureCoherence.lean,Mathlib/Tactic/CategoryTheory/MonoidalComp.lean,MathlibTest/StringDiagram.lean	21	9	['YaelDillies', 'github-actions', 'grunweg', 'imbrem', 'kim-em', 'leanprover-community-bot-assistant']	nobody	419-5634 1 year ago	unknown	unknown
20873	vbeffara author:vbeffara	feat(Topology/Covering): path lifting and homotopy lifting	This proves the existence and uniqueness of path and homotopy lifts through covering maps. --- I tried to separate as much of the proof as possible into separate PRs (which are already in Mathlib now), but the proof here relies on a monolithic construction of an explicit lift along a well-chosen subdivision, in `partial_lift`, with associated definitions. Only one standalone lean file added. An older WIP PR #10084 by Junyan Xu @alreadydone proves similar results using a very similar construction for path lifting, with a different argument to obtain continuity for homotopy lifting. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-topology new-contributor	281/1	Mathlib.lean,Mathlib/Topology/Covering/Basic.lean,Mathlib/Topology/Covering/Lift.lean	3	9	['alreadydone', 'github-actions', 'grunweg', 'vbeffara']	nobody	418-8362 1 year ago	unknown	unknown
20313	thefundamentaltheor3m author:thefundamentaltheor3m	feat(Data/Complex/Exponential): prove some useful results about the complex exponential.	This PR proves two basic results about the complex exponential: * `abs_exp_mul_I (x : ℂ) : abs (Complex.exp (I * x)) = Real.exp (-x.im)` * `one_sub_rexp_re_le_abs_one_sub_cexp (x : ℂ) : 1 - Real.exp x.re ≤ Complex.abs (1 - Complex.exp x)` Both results were proved as part of the sphere packing project. There's a chance they're too specific for mathlib, but I thought they were worth PRing anyway. Would it also be a good idea to tag `abs_exp_mul_I` with `simp`? Feedback/suggestions welcome. Note: `one_sub_rexp_re_le_abs_one_sub_cexp` was proved by Bhavik Mehta @b-mehta --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-analysis new-contributor	167/141	Mathlib.lean,Mathlib/Analysis/Complex/Basic.lean,Mathlib/Analysis/SpecialFunctions/Log/ERealExp.lean,Mathlib/Analysis/SpecialFunctions/Trigonometric/Chebyshev.lean,Mathlib/Data/Complex/Exponential/Defs.lean,Mathlib/Data/Complex/Exponential/Lemmas.lean,Mathlib/Data/Complex/ExponentialBounds.lean,Mathlib/Tactic/FunProp.lean,MathlibTest/Recall.lean,MathlibTest/positivity.lean	10	12	['b-mehta', 'github-actions', 'kim-em', 'thefundamentaltheor3m', 'trivial1711']	nobody	410-65960 1 year ago	unknown	unknown
20730	kuotsanhsu author:kuotsanhsu	feat(LinearAlgebra/Matrix/SchurTriangulation): prove Schur decomposition/triangulation	`Matrix.schur_triangulation` shows that a matrix over an algebraically closed field is unitarily similar to an upper triangular matrix --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-algebra new-contributor label:t-algebra$	317/2	Mathlib.lean,Mathlib/LinearAlgebra/Matrix/Block.lean,Mathlib/LinearAlgebra/Matrix/SchurTriangulation.lean,Mathlib/Logic/Equiv/Basic.lean	4	14	['eric-wieser', 'github-actions', 'kim-em', 'kuotsanhsu']	nobody	410-62092 1 year ago	unknown	unknown
22809	b-reinke author:b-reinke	feat: Category algebras and path algebras	This PR defines the category algebra of a linear category and path algebras of quivers. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-algebra t-category-theory new-contributor label:t-algebra$	218/0	Mathlib/Algebra/Ring/Assoc.lean,Mathlib/CategoryTheory/Linear/CategoryAlgebra.lean,Mathlib/Combinatorics/Quiver/PathAlgebra.lean,Mathlib/Data/DFinsupp/BigOperators.lean	4	2	['b-reinke', 'github-actions']	nobody	395-26531 1 year ago	unknown	unknown
15654	TpmKranz author:TpmKranz	feat(Computability): language-preserving maps between NFA and RE	Map REs to NFAs via Thompson's construction and NFAs to REs using GNFAs Last chunk of #12648 --- - [ ] depends on: #15651 - [ ] depends on: #15649 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	blocked-by-other-PR new-contributor t-computability merge-conflict awaiting-zulip	985/2	Mathlib.lean,Mathlib/Computability/GNFA.lean,Mathlib/Computability/Language.lean,Mathlib/Computability/NFA.lean,Mathlib/Computability/RegularExpressions.lean,Mathlib/Data/FinEnum/Option.lean,docs/references.bib	7	3	['github-actions', 'leanprover-community-mathlib4-bot', 'meithecatte']	nobody	392-59210 1 year ago	unknown	unknown
24008	meithecatte author:meithecatte	chore(EpsilonNFA): replace manual lemmas with @[simps]	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-computability awaiting-author new-contributor	2/24	Mathlib/Computability/EpsilonNFA.lean	1	2	['YaelDillies', 'github-actions', 'urkud']	nobody	387-18389 1 year ago	unknown	unknown
23349	BGuillemet author:BGuillemet	feat: add LocallyLipschitzOn.lipschitzOnWith_of_isCompact and two small lemmas about Lipschitz functions	Main feat (in Mathlib/Topology/EMetricSpace/Basic.lean): if a function `f` from an extended pseudometric space to a pseudometric space is locally Lipschitz on a compact subset `s`, then `f` is Lipschitz on `s`. The theorem is true only when the codomain of `f` is a pseudometric space, so it needs imports from Mathlib/Topology/MetricSpace. Other small feat (in Mathlib/Analysis/Calculus/ContDiff/RCLike.lean): a function that is continuously differentiable on an open subset is locally Lipschitz on this subset. --- - [ ] depends on: #22890 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-topology large-import new-contributor	59/4	Mathlib/Analysis/Calculus/ContDiff/RCLike.lean,Mathlib/Topology/EMetricSpace/Lipschitz.lean	2	4	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot']	PatrickMassot assignee:PatrickMassot	370-77130 1 year ago	unknown	unknown
12799	jstoobysmith author:jstoobysmith	feat(LinearAlgebra/UnitaryGroup): Add properties of Special Unitary Group	Add properties of the special unitary group, mirroring the properties of found in Algebra/Star/Unitary.lean. In particular, I add an instance of `specialUnitaryGroup` as a `Group`, `Star`, `InvolutiveStar`, and `StarMul`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt t-algebra new-contributor merge-conflict awaiting-author label:t-algebra$	78/0	Mathlib/LinearAlgebra/UnitaryGroup.lean	1	8	['chrisflav', 'jcommelin', 'leanprover-community-bot-assistant']	nobody	360-49083 11 months ago	unknown	unknown
20334	miguelmarco author:miguelmarco	feat: allow polyrith to use a local Singular/Sage install	Try to call a local install of Singular (either standalone or inside Sage) to find the witness for polyrith before trying to call the online sage cell server. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author new-contributor t-meta	171/48	Mathlib/Tactic/Polyrith.lean,scripts/polyrith_sage.py	2	16	['eric-wieser', 'github-actions', 'hanwenzhu', 'kim-em', 'miguelmarco', 'mkoeppe']	nobody	353-41636 11 months ago	unknown	unknown
25218	kckennylau author:kckennylau	feat(AlgebraicGeometry): Tate normal form of elliptic curves	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebraic-geometry awaiting-zulip new-contributor	291/26	Mathlib.lean,Mathlib/AlgebraicGeometry/EllipticCurve/IsomOfJ.lean,Mathlib/AlgebraicGeometry/EllipticCurve/Modular/TateNormalForm.lean,Mathlib/AlgebraicGeometry/EllipticCurve/NormalForms.lean,Mathlib/AlgebraicGeometry/EllipticCurve/VariableChange.lean	5	31	['MichaelStollBayreuth', 'Multramate', 'acmepjz', 'github-actions', 'grunweg', 'kckennylau', 'leanprover-community-bot-assistant']	nobody	332-38397 10 months ago	unknown	unknown
10190	jstoobysmith author:jstoobysmith	feat(AlgebraicTopology): add Augmented Simplex Category	- Added the definition of the category FinLinOrd of finite linear ordered sets. - Added the definition of the augmented simplex category `AugmentedSimplexCategory`, and showed it is the Skeleton of FinLinOrd. - Showed that the category of augmented simplicial objects defined as a comma category is equivalent to the category of functors from `AugmentedSimplexCategory^\op` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebraic-topology WIP t-category-theory new-contributor merge-conflict	720/0	Mathlib.lean,Mathlib/AlgebraicTopology/AugmentedSimplexCategory.lean,Mathlib/AlgebraicTopology/SimplicialObject.lean,Mathlib/Order/Category/FinLinOrd.lean	4	5	['TwoFX', 'YaelDillies', 'joelriou', 'jstoobysmith']	nobody	306-10537 10 months ago	unknown	unknown
25238	Hagb author:Hagb	feat(Tactic/ComputeDegree): add support for scalar multiplication with different types	It would be able to deal with `a • (X : R[X])` where `a : S` is in a different type `S` with `[SMulZeroClass S R]`. --- - [x] depends on: #25237 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-meta new-contributor	17/5	Mathlib/Tactic/ComputeDegree.lean,MathlibTest/ComputeDegree.lean	2	3	['github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot']	nobody	302-16728 9 months ago	unknown	unknown
18646	jxjwan author:jxjwan	feat(RingTheory): isotypic components	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory new-contributor	308/0	Mathlib/Order/CompactlyGenerated/Basic.lean,Mathlib/RingTheory/Isotypic.lean,Mathlib/RingTheory/SimpleModule.lean	3	1	['github-actions']	nobody	301-18749 9 months ago	unknown	unknown
20671	thefundamentaltheor3m author:thefundamentaltheor3m	feat(Analysis/Asymptotics/SpecificAsymptotics): Proving that 𝛔ₖ(n) = O(nᵏ⁺¹)	This PR proves a result about the $\sigma_k(n)$ arithmetic function, namely, that it is $O\left(n^{k+1}\right)$. Main theorem: `theorem sigma_asymptotic (k : ℕ) : (fun n ↦ (σ k n : ℝ)) =O[atTop] (fun n ↦ (n ^ (k + 1) : ℝ))` This result was proved as part of the sphere packing project. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor large-import merge-conflict awaiting-author	29/0	Mathlib/Analysis/Asymptotics/SpecificAsymptotics.lean	1	3	['b-mehta', 'github-actions', 'mathlib4-merge-conflict-bot']	b-mehta assignee:b-mehta	296-22290 9 months ago	unknown	unknown
20722	ctchou author:ctchou	feat(Counterexamples): the Vitali set is non-measurable	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt t-measure-probability new-contributor merge-conflict awaiting-author	258/3	Counterexamples.lean,Counterexamples/VitaliSetNotMeasurable.lean,Mathlib/MeasureTheory/Measure/NullMeasurable.lean,docs/1000.yaml	4	76	['ctchou', 'github-actions', 'grunweg', 'mathlib4-merge-conflict-bot', 'vihdzp']	vihdzp assignee:vihdzp	290-11974 9 months ago	unknown	unknown
28502	gilesgshaw author:gilesgshaw	feat(Logic/Basic): avoid unnecessary uses of choice	Certain proofs are modified to remove a dependence on the axoim of choice --- - [ ] depends on: #28623	blocked-by-other-PR new-contributor merge-conflict awaiting-author t-logic	83/74	Mathlib/Logic/Basic.lean	1	7	['Ruben-VandeVelde', 'eric-wieser', 'gilesgshaw', 'github-actions', 'kim-em', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	287-33786 9 months ago	290-19315 290 days ago	0-32456 9 hours
19582	yu-yama author:yu-yama	feat(GroupExtension/Abelian): define `OfMulDistribMulAction.equivH2`	Mainly defines: - `structure GroupExtension.OfMulDistribMulAction N G [MulDistribMulAction G N]`: group extensions of `G` by `N` where the multiplicative action of `G` on `N` is the conjugation - `structure GroupExtension.OfMulDistribMulActionWithSection N G [MulDistribMulAction G N]`: group extensions with specific choices of sections - `def GroupExtension.OfMulDistribMulAction.equivH2`: a bijection between the equivalence classes of group extensions and $H^2 (G, N)$ --- - [x] depends on: #20802 (split PR: contains changes to the `Defs` file) - [x] depends on: #20998 (split PR: mainly adds the `Basic` file) - [ ] depends on: #26670 (split PR: adds the first part of the `Abelian` file) Here is a relevant TODO in Mathlib: https://github.com/leanprover-community/mathlib4/blob/4e9fa40d7c480937e09cd6e47a591bd6f3b8be42/Mathlib/RepresentationTheory/GroupCohomology/LowDegree.lean#L46-L48 I would appreciate your comments. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-algebra blocked-by-other-PR new-contributor label:t-algebra$	750/14	Mathlib.lean,Mathlib/GroupTheory/GroupExtension/Abelian.lean,Mathlib/GroupTheory/GroupExtension/Defs.lean,docs/references.bib	4	5	['YaelDillies', 'erdOne', 'github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	284-70294 9 months ago	unknown	unknown
27403	MoritzBeroRoos author:MoritzBeroRoos	fix: replace probably erroneous usage of ⬝ (with old \cdot) by · (with \centerdot)	Discussion at [zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/.5Ccdot.20!.3D.20.5Ccenterdot). Currently the abbreviations \cdot and \centerdot resolve to different, with the naked eye nearly undistinguishable symbols (despite the c in cdot surely standing for center..). This pr replaces instances of ⬝ where · was probably meant. All of the replacement is in comments, except for the file bench_summary.lean which is used for priting the github benchmark results. Since this file is about scientific notation of numbers, sure · was meant to be used, not a rectangle. [Related](https://github.com/leanprover-community/mathlib4/pull/27399) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict new-contributor	195/195	Mathlib/Algebra/ContinuedFractions/Computation/Approximations.lean,Mathlib/Algebra/DirectSum/Idempotents.lean,Mathlib/Algebra/Lie/Derivation/Basic.lean,Mathlib/Algebra/Module/Equiv/Basic.lean,Mathlib/AlgebraicGeometry/EllipticCurve/DivisionPolynomial/Basic.lean,Mathlib/Analysis/Analytic/Constructions.lean,Mathlib/Analysis/CStarAlgebra/CStarMatrix.lean,Mathlib/Analysis/Calculus/ContDiff/Basic.lean,Mathlib/Analysis/Calculus/ContDiff/Bounds.lean,Mathlib/Analysis/Calculus/FDeriv/Symmetric.lean,Mathlib/Analysis/Fourier/FourierTransformDeriv.lean,Mathlib/Analysis/InnerProductSpace/Dual.lean,Mathlib/Analysis/InnerProductSpace/PiL2.lean,Mathlib/Analysis/Normed/Unbundled/InvariantExtension.lean,Mathlib/Analysis/SpecialFunctions/Complex/CircleAddChar.lean,Mathlib/Combinatorics/Configuration.lean,Mathlib/Combinatorics/SimpleGraph/AdjMatrix.lean,Mathlib/Combinatorics/SimpleGraph/LapMatrix.lean,Mathlib/Data/Matrix/Block.lean,Mathlib/Data/Matrix/ConjTranspose.lean,Mathlib/Data/Matrix/Hadamard.lean,Mathlib/Data/Matrix/Mul.lean,Mathlib/Data/Matrix/Notation.lean,Mathlib/Data/Matrix/Reflection.lean,Mathlib/Data/Matrix/RowCol.lean,Mathlib/Data/Matrix/Vec.lean,Mathlib/FieldTheory/PurelyInseparable/PerfectClosure.lean,Mathlib/Geometry/Manifold/GroupLieAlgebra.lean,Mathlib/GroupTheory/Coxeter/Matrix.lean,Mathlib/LinearAlgebra/CrossProduct.lean,Mathlib/LinearAlgebra/Matrix/BilinearForm.lean,Mathlib/LinearAlgebra/Matrix/DotProduct.lean,Mathlib/LinearAlgebra/Matrix/Nondegenerate.lean,Mathlib/LinearAlgebra/Matrix/Orthogonal.lean,Mathlib/LinearAlgebra/Matrix/PosDef.lean,Mathlib/LinearAlgebra/Matrix/SchurComplement.lean,Mathlib/LinearAlgebra/Matrix/SesquilinearForm.lean,Mathlib/LinearAlgebra/Matrix/Trace.lean,Mathlib/LinearAlgebra/Multilinear/Basic.lean,Mathlib/LinearAlgebra/PerfectPairing/Matrix.lean,Mathlib/LinearAlgebra/Projectivization/Constructions.lean,Mathlib/NumberTheory/NumberField/ProductFormula.lean,Mathlib/NumberTheory/SiegelsLemma.lean,Mathlib/RingTheory/DividedPowers/SubDPIdeal.lean,Mathlib/SetTheory/Ordinal/Veblen.lean,Mathlib/Topology/Algebra/Module/Equiv.lean,Mathlib/Topology/Homeomorph/Lemmas.lean,Mathlib/Topology/Instances/Matrix.lean,scripts/bench_summary.lean	49	5	['eric-wieser', 'github-actions', 'grunweg', 'leanprover-community-bot-assistant']	nobody	283-34875 9 months ago	306-10797 306 days ago	7-54020 7 days
27399	MoritzBeroRoos author:MoritzBeroRoos	chore: replace every usage of ⬝ᵥ (with old \cdot) by ·ᵥ (with \centerdot)	Discussion at [zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/.5Ccdot.20!.3D.20.5Ccenterdot). Currently the abbreviations `\cdot` and `\centerdot` resolve to different, with the naked eye nearly undistinguishable symbols (despite the c in cdot surely standing for `center`..): - `\cdot` gives ⬝ [U+2B1D](https://www.compart.com/en/unicode/U+2B1D) "Black Very Small Square" - `\centerdot` gives · [U+00B7](https://www.compart.com/en/unicode/U+00B7) "Middle Dot" Mathlib mostly uses the `\centerdot` variant, except for the dotProduct notation and some probably unsuspecting people wanting \centerdot but getting \cdot in their comments and 6 uses of a notation using the raw `\cdot` without any subscript at `Mathlib\Topology\Homotopy\Product.lean`. This PR replaces the dot product `⬝ᵥ` with its `\centerdot` counterpart `·ᵥ`. The related PR [here](https://github.com/leanprover/vscode-lean4/pull/639) can then overwrite the `\cdot` abbreviation, to produce the same symbol as the `centerdot` abbreviation does. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict new-contributor	133/133	Mathlib/Analysis/CStarAlgebra/CStarMatrix.lean,Mathlib/Analysis/InnerProductSpace/PiL2.lean,Mathlib/Combinatorics/Configuration.lean,Mathlib/Combinatorics/SimpleGraph/AdjMatrix.lean,Mathlib/Combinatorics/SimpleGraph/LapMatrix.lean,Mathlib/Data/Matrix/Block.lean,Mathlib/Data/Matrix/ConjTranspose.lean,Mathlib/Data/Matrix/Hadamard.lean,Mathlib/Data/Matrix/Mul.lean,Mathlib/Data/Matrix/Notation.lean,Mathlib/Data/Matrix/Reflection.lean,Mathlib/Data/Matrix/RowCol.lean,Mathlib/Data/Matrix/Vec.lean,Mathlib/LinearAlgebra/CrossProduct.lean,Mathlib/LinearAlgebra/Matrix/BilinearForm.lean,Mathlib/LinearAlgebra/Matrix/DotProduct.lean,Mathlib/LinearAlgebra/Matrix/Nondegenerate.lean,Mathlib/LinearAlgebra/Matrix/Orthogonal.lean,Mathlib/LinearAlgebra/Matrix/PosDef.lean,Mathlib/LinearAlgebra/Matrix/SchurComplement.lean,Mathlib/LinearAlgebra/Matrix/SesquilinearForm.lean,Mathlib/LinearAlgebra/Matrix/Trace.lean,Mathlib/LinearAlgebra/PerfectPairing/Matrix.lean,Mathlib/LinearAlgebra/Projectivization/Constructions.lean,Mathlib/Topology/Instances/Matrix.lean	25	6	['MoritzBeroRoos', 'eric-wieser', 'github-actions', 'leanprover-community-bot-assistant']	nobody	282-83107 9 months ago	306-10798 306 days ago	7-54958 7 days
27479	iu-isgood author:iu-isgood	feat: Abel's Binomial Theorem	We have formalized Abel's Binomial Theorem as part of an REU project. There are a few remaining sorrys, but we will finish them soon. I will edit this PR message later according to community rules. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-data new-contributor	326/0	Mathlib/Data/Nat/Choose/AbelBinomial.lean	1	28	['ElifUskuplu', 'FrankieNC', 'github-actions', 'iu-isgood']	nobody	282-82868 9 months ago	unknown	unknown
26462	PSchwahn author:PSchwahn	feat(LinearAlgebra/Projection): add results about inverse of `Submodule.prodEquivOfIsCompl`	Add two theorems `Submodule.prodEquivOfIsCompl_symm_apply` and `Submodule.prodEquivOfIsCompl_symm_add`, which are API for `Submodule.prodEquivOfIsCompl`. We believe these theorems are useful; for example, we have used their statements in a [classification formalization project](https://github.com/LieLean/LowDimSolvClassification). Co-authored by: - [Viviana del Barco](https://github.com/vdelbarc) - [Gustavo Infanti](https://github.com/GuQOliveira) - [Exequiel Rivas](https://github.com/erivas) --- I am not sure whether the `prodEquivOfIsCompl_symm_apply` theorem should be tagged with `@[simp]`; this might lead to confluence issues. Opinions are welcome! [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-algebra new-contributor label:t-algebra$	10/0	Mathlib/LinearAlgebra/Projection.lean	1	7	['PSchwahn', 'github-actions', 'joelriou', 'kckennylau']	joelriou assignee:joelriou	266-54236 8 months ago	266-85339 266 days ago	71-82192 71 days
28623	gilesgshaw author:gilesgshaw	feat(Logic/Basic): minor additions and simplification of proofs	Add new theorems and simplify proofs. Specifically, we add the family of related theorems `apply_dite_iff_exists`, `apply_dite_iff_forall`, `apply_ite_iff_and` and `apply_ite_iff_or`. For each other 'family' of theorems in the file that is analogous to the above, we do the following - Simplify proofs where possible, e.g. by appealing to the new theorems - Complete the family, if any of the corresponding four are missing - Rename to ensure consistency with the above pattern ---	merge-conflict t-logic new-contributor	83/55	Archive/Examples/IfNormalization/Result.lean,Archive/Examples/IfNormalization/WithoutAesop.lean,Mathlib/Algebra/ContinuedFractions/Computation/Translations.lean,Mathlib/Algebra/MvPolynomial/Variables.lean,Mathlib/Algebra/Notation/Indicator.lean,Mathlib/LinearAlgebra/Matrix/Rank.lean,Mathlib/Logic/Basic.lean,Mathlib/MeasureTheory/Measure/WithDensity.lean,Mathlib/SetTheory/Ordinal/Notation.lean	9	12	['eric-wieser', 'gilesgshaw', 'github-actions', 'mathlib4-merge-conflict-bot', 'plp127']	awainverse assignee:awainverse	266-2738 8 months ago	266-2739 266 days ago	10-52803 10 days
25778	thefundamentaltheor3m author:thefundamentaltheor3m	feat: Monotonicity of `setIntegral` for nonnegative functions	This PR makes it easier to prove monotonicity of the Bochner integral on sets for nonnegative functions by removing the stronger assumption required by the general monotonicity lemma that both of the functions being compared must be integrable. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-measure-probability new-contributor	8/0	Mathlib/MeasureTheory/Integral/Bochner/Set.lean	1	6	['RemyDegenne', 'github-actions', 'sgouezel', 'thefundamentaltheor3m']	nobody	263-84860 8 months ago	unknown	unknown
29588	Periecle author:Periecle	feat(Analysis/Complex/Residue): Implement residue theory for complex functions at isolated singularities	# Add basic residue theory for complex functions This PR introduces the residue theory implementation in mathlib. ## Main additions - `HasIsolatedSingularityAt f c`: Predicate for functions with isolated singularities at point `c` - `residue f c hf`: The residue of `f` at isolated singularity `c`, defined via circle integrals - Radius independence: `residue_eq_two_pi_I_inv_smul_circleIntegral` - residue equals normalized circle integral for any valid radius - Holomorphic residues: `residue_of_holomorphic` - functions holomorphic in a neighborhood have zero residue - Simple pole formula: `residue_simple_pole` - for `f(z) = (z-c)⁻¹ * g(z)`, residue equals `g(c)` ## Implementation notes - Builds on existing circle integral infrastructure in `CauchyIntegral.lean` - Uses `Classical.choose` to extract witness radius from isolated singularity condition - Comprehensive documentation with mathematical context and examples - Establishes foundation for residue theorem, argument principle, and other applications ## Examples included - `residue(1/z, 0) = 1` (canonical simple pole) - Radius independence demonstration - Zero residues for holomorphic functions This provides the essential building blocks for complex analysis and first step to formalize residue theory.	awaiting-author t-analysis new-contributor	383/0	Mathlib/Analysis/Complex/Residue/Basic.lean	1	17	['Periecle', 'github-actions', 'hrmacbeth', 'llllvvuu', 'loefflerd']	nobody	251-1938 8 months ago	unknown	unknown
26178	ppls-nd-prs author:ppls-nd-prs	feat(CategoryTheory/Limits): Fubini for products	We show that the product of products is a product indexed by the sigma type. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-category-theory new-contributor	17/0	Mathlib/CategoryTheory/Limits/Shapes/Products.lean	1	6	['chrisflav', 'github-actions', 'leanprover-community-bot-assistant', 'ppls-nd-prs', 'robin-carlier']	nobody	246-16982 8 months ago	347-26382 347 days ago	0-46446 12 hours
28630	Antidite author:Antidite	feat(Archive/Imo): right isosceles configuration in the complex plane	feat(Archive/Imo): right isosceles configuration in the complex plane This adds `Archive/Imo/Imo1975Q3.lean`, formalizing a triangle configuration with points A=0, B=1, C=z and auxiliary points R, P, Q built via complex rotations and sine-based scale factors. Main results: * `angle_and_distance`: ∠QRP = π/2 and dist Q R = dist R P. * Key identity `QRP_rot90`: (Q z).z − R.z = e^{iπ/2} · ((P z).z − R.z). Design/Style: * Minimal imports; module docstring; semantic lemma names; all definitions and theorems live under the namespace `IMO.TriangleConfig`. Moves: - (none) Deletions: - (none) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	IMO awaiting-author new-contributor	196/0	Archive.lean,Archive/Imo/Imo1975Q3.lean	2	36	['Antidite', 'LLaurance', 'github-actions', 'jsm28']	jsm28 assignee:jsm28	240-69128 7 months ago	240-69128 240 days ago	46-25040 46 days
16773	arulandu author:arulandu	feat(Probability/Distributions): formalize Beta distribution	Formalize Beta distribution, using Gamma distribution as a reference. Added real-valued beta wrapper, in the manner of gamma. Thanks to @EtienneC30 for help with casting real <-> complex. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author new-contributor t-measure-probability	286/1	Mathlib.lean,Mathlib/Analysis/SpecialFunctions/Gamma/Beta.lean,Mathlib/Probability/Distributions/Beta.lean	3	50	['EtienneC30', 'arulandu', 'github-actions', 'mathlib4-merge-conflict-bot', 'vihdzp']	arulandu assignee:arulandu	234-78433 7 months ago	unknown	unknown
30460	janithamalith author:janithamalith	feat(Nat): add lemma nat_card_orbit_mul_card_stabilizer_eq_card_group	Added a lemma `nat_card_orbit_mul_card_stabilizer_eq_card_group` which is the Nat.card version of MulAction.card_orbit_mul_card_stabilizer_eq_card_group --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-group-theory new-contributor	6/0	Mathlib/GroupTheory/GroupAction/CardCommute.lean	1	17	['github-actions', 'kckennylau', 'plp127', 'tb65536']	tb65536 assignee:tb65536	225-2283 7 months ago	225-2283 225 days ago	8-6812 8 days
25225	xcloudyunx author:xcloudyunx	feat(Combinatorics/SimpleGraph): Eulerian walk in connected graph contains all vertices	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-combinatorics new-contributor	16/0	Mathlib/Combinatorics/SimpleGraph/Trails.lean	1	6	['IvanRenison', 'github-actions', 'vlad902']	kmill assignee:kmill	223-52215 7 months ago	unknown	unknown
30828	DeVilhena-Paulo author:DeVilhena-Paulo	feat: implementation of `Finmap.merge`	The main contribution of this pull request is the implementation of a `merge` function for finite maps (`Finmap`). The construction relies on the definition of a `merge` function for association lists (`AList`). There is also a side (unrelated) contribution on `Mathlib/Data/List/Permutation.lean`: the addition of a theorem about the permutation of a list with a head element (that is, a list of the form `a :: l`). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor	449/3	Mathlib/Data/Finmap.lean,Mathlib/Data/List/AList.lean,Mathlib/Data/List/Permutation.lean,Mathlib/Data/List/Sigma.lean	4	1	['github-actions']	nobody	221-75647 7 months ago	unknown	unknown
28676	sun123zxy author:sun123zxy	feat(NumberTheory/ArithmeticFunction): wrap `Nat.totient` as an `ArithmeticFunction`	This wraps the Euler's totient function `Nat.totient` into a new `ArithmeticFunction` `ϕ`, with some basic identities such as `ϕ * ζ = id` and `μ * id = ϕ.` --- We use the notation `ϕ` to distinguish from `Nat.totient`'s notation `φ`, however this might be controversial. Suggestions are welcome! [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor large-import merge-conflict awaiting-author	45/5	Mathlib/NumberTheory/ArithmeticFunction.lean	1	19	['MichaelStollBayreuth', 'SnirBroshi', 'b-mehta', 'eric-wieser', 'github-actions', 'mathlib4-merge-conflict-bot', 'riccardobrasca', 'sun123zxy']	MichaelStollBayreuth assignee:MichaelStollBayreuth	217-21686 7 months ago	232-82762 232 days ago	47-17222 47 days
30299	franv314 author:franv314	feat(Topology/Instances): Cantor set	Prove that the Cantor set has empty interior and the cardinality of the continuum as discussed on [Zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/A.20few.20results.20about.20the.20Cantor.20set/with/543560670) Moves: - Mathlib.Topology.Instances.CantorSet -> Mathlib.Topology.Instances.CantorSet.Basic --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict file-removed awaiting-author t-topology	355/2	Mathlib.lean,Mathlib/Topology/Instances/CantorSet/Basic.lean,Mathlib/Topology/Instances/CantorSet/Cardinality.lean,Mathlib/Topology/Instances/CantorSet/Lemmas.lean	4	5	['github-actions', 'grunweg', 'kckennylau', 'mathlib4-merge-conflict-bot']	nobody	217-13416 7 months ago	237-82445 237 days ago	0-553 9 minutes
30303	franv314 author:franv314	chore(Topology/Instances): add deprecated module	Add deprecated module to moved Cantor set file. --- - [ ] depends on: #30299 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR new-contributor	486/124	Mathlib.lean,Mathlib/Topology/Instances/CantorSet.lean,Mathlib/Topology/Instances/CantorSet/Basic.lean,Mathlib/Topology/Instances/CantorSet/Cardinality.lean,Mathlib/Topology/Instances/CantorSet/Lemmas.lean	5	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	217-13414 7 months ago	237-80314 237 days ago	0-308 5 minutes
29871	zach1502 author:zach1502	feat(Matrix/Transvection): Gauss pivot determinant identity and pivot preservation	This PR adds two lemmas formalizing standard Gaussian pivot identities: * `Matrix.Transvection.listTransvecCol_mul_mul_listTransvecRow_pivot`: After applying the canonical left/right transvection products that clear the last column and row, the pivot (bottom-right) entry of a matrix is unchanged. Marked `@[simp]`. * `Matrix.Transvection.det_eq_detTopLeft_mul_pivot`: If the pivot entry is nonzero, then the determinant of the matrix factors as the determinant of the top-left block times the pivot entry, after performing the canonical transvections. This is the usual Gauss–pivot determinant identity. * Added simple usage tests in `MathlibTest/matrix.lean` to check that the new lemmas are usable by `simp`/`simpa`. --- --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-algebra new-contributor label:t-algebra$	94/0	Mathlib/LinearAlgebra/Matrix/Transvection.lean,MathlibTest/matrix.lean	2	3	['github-actions', 'riccardobrasca', 'zach1502']	nobody	211-12937 6 months ago	211-12937 211 days ago	41-53435 41 days
30158	nicolaviolette author:nicolaviolette	feat: combinatorics simplegraph basic	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-combinatorics new-contributor	9/4	Mathlib/Combinatorics/SimpleGraph/Basic.lean	1	3	['b-mehta', 'github-actions']	b-mehta assignee:b-mehta	210-32467 6 months ago	unknown	unknown
26901	5hv5hvnk author:5hv5hvnk	feat: a simproc version of `compute_degree`	Wrap `compute_degree` in a simproc for use by simp. Closes #22219. ---	awaiting-CI new-contributor merge-conflict awaiting-author t-meta	198/0	Mathlib.lean,Mathlib/Tactic/Simproc/PolynomialDegree.lean,MathlibTest/polynomial_degree_simproc.lean	3	19	['5hv5hvnk', 'YaelDillies', 'adomani', 'github-actions', 'mathlib4-merge-conflict-bot']	nobody	207-79135 6 months ago	unknown	unknown
30150	imbrem author:imbrem	feat(CategoryTheory/Monoidal): to_additive for MonoidalCategory	Add `AddMonoidalCategory`, the additive version of `MonoidalCategory`. To get this to work, I needed to _remove_ the `to_additive` attributes in `Discrete.lean`, since existing code relies on the `AddMonoid M → MonoidalCategory M` instance. For now, we simply implement the additive variants by hand instead. --- As discussed in #28718; I added an `AddMonoidalCategory` struct and tagged `MonoidalCategory` with `to_additive`, along with the lemmas in `Category.lean`. I think this is the right approach, since under this framework the "correct" additive version of `Discrete.lean` would be mapping an `AddMonoid` to an `AddMonoidalCategory`. Next steps would be to: - Make `monoidal_coherence` and `coherence` support `AddMonoidalCategory` - Add `CocartesianMonoidalCategory` extending `AddMonoidalCategory` [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-category-theory large-import new-contributor merge-conflict awaiting-zulip t-meta	444/125	Mathlib/CategoryTheory/Monoidal/Category.lean,Mathlib/CategoryTheory/Monoidal/Discrete.lean,Mathlib/Tactic/ToAdditive/GuessName.lean	3	22	['JovanGerb', 'YaelDillies', 'github-actions', 'imbrem', 'mathlib4-merge-conflict-bot']	nobody	201-42126 6 months ago	241-20792 241 days ago	0-29227 8 hours
15651	TpmKranz author:TpmKranz	feat(Computability/NFA): operations for Thompson's construction	Lays the groundwork for a proof of equivalence of RE and NFA, w.r.t. described language. Actual connection to REs comes later, after the groundwork for the opposite direction has been laid. Third chunk of #12648 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-computability merge-conflict awaiting-author awaiting-zulip	307/5	Mathlib/Computability/NFA.lean	1	27	['TpmKranz', 'YaelDillies', 'dupuisf', 'github-actions', 'leanprover-community-bot-assistant', 'meithecatte', 'rudynicolop']	nobody	196-59258 6 months ago	unknown	unknown
15649	TpmKranz author:TpmKranz	feat(Computability): introduce Generalised NFA as bridge to Regular Expression	Lays the groundwork for a proof of equivalence of NFA and RE, w.r.t. described language. Actual connection to NFA comes later, after the groundwork for the opposite direction has been laid. Second chunk of #12648 --- - [x] depends on: #15647 [Data.FinEnum.Option unchanged since then] [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-computability merge-conflict awaiting-author awaiting-zulip	298/0	Mathlib.lean,Mathlib/Computability/GNFA.lean,Mathlib/Computability/Language.lean,Mathlib/Computability/RegularExpressions.lean,docs/references.bib	5	7	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'meithecatte', 'trivial1711']	nobody	195-75499 6 months ago	unknown	unknown
5919	MithicSpirit author:MithicSpirit	feat: implement orthogonality for AffineSubspace	Define `AffineSubspace.orthogonal` and `AffineSubspace.IsOrtho`, as well as develop an API emulating that of `Submodule.orthogonal` and `Submodule.IsOrtho`, respectively. Additionally, provide some relevant lemmas exclusive to affine subspaces, which are mostly to do with the relationship between orthogonality and `AffineSubspace.Parallel`. Closes #5539 --- Still WIP as I need to add more docstrings as well as notations for the new definitions. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP new-contributor merge-conflict help-wanted t-analysis	287/0	Mathlib.lean,Mathlib/Analysis/InnerProductSpace/AffineSubspace.lean	2	7	['MithicSpirit', 'eric-wieser', 'github-actions', 'leanprover-community-bot-assistant', 'mathlib4-merge-conflict-bot']	MithicSpirit assignee:MithicSpirit	195-26956 6 months ago	unknown	unknown
13442	dignissimus author:dignissimus	feat: mabel tactic for multiplicative abelian groups	Mabel tactic for multiplicative abelian groups (#10361) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict modifies-tactic-syntax awaiting-author help-wanted t-meta	439/0	Mathlib.lean,Mathlib/Tactic.lean,Mathlib/Tactic/MAbel.lean,MathlibTest/mabel.lean	4	11	['BoltonBailey', 'dignissimus', 'github-actions', 'joneugster', 'kbuzzard', 'mathlib4-merge-conflict-bot']	joneugster assignee:joneugster	195-26692 6 months ago	unknown	unknown
14237	js2357 author:js2357	feat: Define the localization of a fractional ideal at a prime ideal	Define the localization of a fractional ideal at a prime ideal, and prove some basic properties. --- This PR is part 3 out of 4 of a proof of `isDedekindDomain_iff_isDedekindDomainDvr`. Part 4 is available here: #14242 - [x] depends on: #14099 Part 1 - [x] depends on: #14216 Part 2 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-algebra new-contributor label:t-algebra$	230/0	Mathlib.lean,Mathlib/RingTheory/FractionalIdeal/LocalizedAtPrime.lean,Mathlib/RingTheory/Localization/Basic.lean	3	22	['Vierkantor', 'YaelDillies', 'github-actions', 'js2357', 'kbuzzard', 'leanprover-community-bot-assistant', 'leanprover-community-mathlib4-bot', 'mathlib4-merge-conflict-bot']	Vierkantor assignee:Vierkantor	195-26690 6 months ago	unknown	unknown
15224	AnthonyBordg author:AnthonyBordg	feat(CategoryTheory/Sites): covering families and their associated Grothendieck topology	Define covering families on a category and their associated Grothendieck topology by using the API for `Coverage`. Give an explicit characterization of the covering sieves of the said topology. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-category-theory new-contributor	112/0	Mathlib.lean,Mathlib/CategoryTheory/Sites/CoveringFamilies.lean	2	21	['AnthonyBordg', 'adamtopaz', 'dagurtomas', 'github-actions', 'joelriou', 'mathlib4-merge-conflict-bot']	nobody	195-26561 6 months ago	unknown	unknown
17587	kmill author:kmill	feat: Sym2-as-Finset theory	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-data new-contributor	105/3	Mathlib/Combinatorics/SimpleGraph/Basic.lean,Mathlib/Combinatorics/SimpleGraph/Finite.lean,Mathlib/Data/Sym/Sym2.lean,Mathlib/RingTheory/Polynomial/Vieta.lean	4	11	['FordUniver', 'YaelDillies', 'github-actions', 'kmill', 'mathlib4-merge-conflict-bot']	nobody	195-26407 6 months ago	unknown	unknown
18630	tomaz1502 author:tomaz1502	feat(Computability.Timed): Formalization of runtime complexity of List.mergeSort	This PR adds the formalization of the runtime complexity of the merge sort algorithm, defined in `Data/List/Sort`. Requires: https://github.com/leanprover-community/mathlib4/pull/15451 References: - Previous PR on mathlib3: https://github.com/leanprover-community/mathlib3/pull/14494/ - First discussion on Zulip: https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/BSc.20Final.20Project/near/220647062 - Second disussion on Zulip: https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Formalization.20of.20Runtime.20Complexity.20of.20Sorting.20Algorithms/near/284184450 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-computability new-contributor	526/0	Mathlib.lean,Mathlib/Computability/Timed/InsertionSort.lean,Mathlib/Computability/Timed/Merge.lean,Mathlib/Computability/Timed/MergeSort.lean,Mathlib/Computability/Timed/Split.lean	5	9	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	195-26405 6 months ago	unknown	unknown
20648	anthonyde author:anthonyde	feat: formalize regular expression -> εNFA	The file `Computability/RegularExpressionsToEpsilonNFA.lean` contains a formal definition of Thompson's method for constructing an `εNFA` from a `RegularExpression` and a proof of its correctness. --- - [x] depends on: #20644 - [x] depends on: #20645 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-computability awaiting-zulip new-contributor	490/0	Mathlib.lean,Mathlib/Computability/RegularExpressionsToEpsilonNFA.lean,docs/references.bib	3	7	['anthonyde', 'github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'meithecatte', 'qawbecrdtey']	nobody	195-26267 6 months ago	unknown	unknown
21903	yhtq author:yhtq	feat: add from/toList between `FreeSemigroup` and `List` with relative theorems	Add from/toList between `FreeSemigroup` and `List` with relative theorems, as well as an incidental definition of lexicographic order on `FreeSemigroup`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-CI large-import merge-conflict label:t-algebra$	169/0	Mathlib/Algebra/Free.lean	1	12	['YaelDillies', 'github-actions', 'mathlib4-merge-conflict-bot']	nobody	195-26127 6 months ago	unknown	unknown
22159	shetzl author:shetzl	feat: add definition of pushdown automata	Add the definition of pushdown automata and their two acceptance conditions: acceptance based on empty stack and acceptance based on final state. Co-authored-by: Tobias Leichtfried --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-computability awaiting-author new-contributor	70/0	Mathlib.lean,Mathlib/Computability/PDA.lean	2	35	['YaelDillies', 'github-actions', 'madvorak', 'mathlib4-merge-conflict-bot', 'shetzl']	nobody	195-26121 6 months ago	unknown	unknown
22302	658060 author:658060	feat: add `CategoryTheory.Topos.Power`	This is a continuation of #21281 with the end goal of defining topoi in Mathlib. It introduces the notion of a power object in a category with a subobject classifier, which is a special case of an internal hom. The definition `HasPowerObjects C` contained in this PR is all that remains before `IsTopos C` can be defined. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-category-theory new-contributor	312/0	Mathlib.lean,Mathlib/CategoryTheory/Topos/Power.lean	2	3	['github-actions', 'joelriou', 'mathlib4-merge-conflict-bot']	b-mehta assignee:b-mehta	195-26112 6 months ago	unknown	unknown
22790	mhk119 author:mhk119	feat: Extend `taylor_mean_remainder_lagrange` to `x < x_0`	The `taylor_mean_remainder_lagrange` theorem has the assumption that $x_0 < x$. In many applications, we need $x < x_0$ and one cannot use the current version to obtain this (see [zulip](https://leanprover.zulipchat.com/#narrow/channel/116395-maths/topic/Taylor's.20theorem)). This PR introduces a set of theorems that push negations through Taylor expansions so that one can extend `taylor_mean_remainder_lagrange` to the case when $x < x_0$. These theorems should also be useful elsewhere since they are quite general.	merge-conflict awaiting-author t-analysis new-contributor	111/1	Mathlib/Analysis/Calculus/Deriv/Basic.lean,Mathlib/Analysis/Calculus/IteratedDeriv/Lemmas.lean,Mathlib/Analysis/Calculus/Taylor.lean	3	13	['Paul-Lez', 'github-actions', 'grunweg', 'mathlib4-merge-conflict-bot', 'mhk119']	nobody	195-26099 6 months ago	unknown	unknown
24333	xcloudyunx author:xcloudyunx	feat(Combinatorics/SimpleGraph): cycle graph implementation for generic vertex types	The existing `cycleGraph` implementation under Combinatorics/SimpleGraph/Circulant.lean only operates over `Fin n`. This PR implements a cycle graph implementation over any generic vertex type. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-combinatorics new-contributor	187/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Cycle.lean	2	42	['IvanRenison', 'github-actions', 'mathlib4-merge-conflict-bot', 'vlad902']	kmill assignee:kmill	195-25946 6 months ago	unknown	unknown
25739	literandltx author:literandltx	feat(NumberTheory/LegendreSymbol): Add sqrt‐of‐residue theorems for p=4k+3 and p=8k+5	Add a new file `QuadraticResidueRoots.lean` under `Mathlib/NumberTheory/LegendreSymbol/` that proves two explicit “square-root of quadratic residue” theorems for primes of the specific form. - `exists_sqrt_of_residue_mod4_eq3` for primes `p = 4k + 3` - `exists_sqrt_of_residue_mod8_eq5`* for primes `p = 8*k + 5` It also introduces the helper lemmas `euler_criterion_traditional` and `legendreSym.at_two_mod8_eq_5`. Import lines in `Mathlib.lean` and `Mathlib/NumberTheory/LegendreSymbol/Basic.lean` have been updated accordingly.	merge-conflict awaiting-author t-number-theory new-contributor	217/0	Mathlib.lean,Mathlib/NumberTheory/LegendreSymbol/Basic.lean,Mathlib/NumberTheory/LegendreSymbol/QuadraticReciprocity.lean,Mathlib/NumberTheory/LegendreSymbol/QuadraticResidueRoots.lean	4	3	['github-actions', 'kckennylau', 'mathlib4-merge-conflict-bot']	literandltx assignee:literandltx	195-25797 6 months ago	unknown	unknown
26165	oliver-butterley author:oliver-butterley	feat(MeasureTheory.VectorMeasure): add lemma which shows that variation of a `ℝ≥0∞` VectorMeasure is equal to itself	Add a lemma for the variation of a VectorMeasure which tells that if `μ` is `VectorMeasure X ℝ≥0∞` then ``μ.ennrealVariation = μ`. Co-authored-by: @yoh-tanimoto --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-measure-probability awaiting-author merge-conflict blocked-by-other-PR new-contributor	467/0	Mathlib/MeasureTheory/VectorMeasure/Variation/Basic.lean,Mathlib/Order/Partition/Finpartition.lean	3	9	['github-actions', 'leanprover-radar', 'mathlib4-merge-conflict-bot', 'oliver-butterley', 'yoh-tanimoto']	nobody	195-25608 6 months ago	unknown	unknown
26300	igorkhavkine author:igorkhavkine	feat(Analysis/Calculus/FDeriv): continuous differentiability from continuous partial derivatives on an open domain in a product space	If a function `f : E × F → G` is continuously differentiable, then its partial derivatives along `E` and `F` are also continuous. The non-trivial converse implication holds when the partial derivatives are continuous on an open domain, and they can be added together to give the total derivative of `f`. See this [#mathlib4 > Partial derivatives @ 💬](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Partial.20derivatives/near/520995477) and the containing thread for some discussion. The PR creates a new import (`Mathlib.Analysis.Calculus.FDeriv.Partial`), where other results about partial derivatives could go in the future. --- this is the migration of #25304 to the PR-from-fork workflow - [x] depends on: #25564 - [x] depends on: #26273 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP new-contributor awaiting-author t-analysis merge-conflict	468/0	Mathlib/Analysis/Calculus/FDeriv/Partial.lean	3	23	['YaelDillies', 'agjftucker', 'github-actions', 'igorkhavkine', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'sgouezel']	sgouezel assignee:sgouezel	195-25585 6 months ago	291-73975 291 days ago	44-76629 44 days
26594	metakunt author:metakunt	feat(Algebra/Polynomial/ZMod): Add Polynomial.equiv_of_nat_of_polynomial_zmod	This adds an explicit bijection between the naturals and $$\mathbb{Z}/n\mathbb{Z}[X]$$ in a canonical way. --- I feel that some API is missing to make the theorem shorter, I have no idea what lemmas to extract though. Also I don't know when to use spaces and when not, so I did it best effort.	merge-conflict awaiting-author t-algebra new-contributor label:t-algebra$	465/0	Mathlib.lean,Mathlib/Algebra/Polynomial/ZMod.lean	2	3	['Ruben-VandeVelde', 'github-actions', 'mathlib4-merge-conflict-bot']	nobody	195-25437 6 months ago	310-69195 310 days ago	25-5171 25 days
26757	fweth author:fweth	feat(CategoryTheory/Topos): define elementary topos	This commit begins the formalization of the notion of an elementary topos, following the definition in \[Mac Lane & Moerdijk, Sheaves in Geometry and Logic (1992), Ch. IV, Section 1]. It introduces the file `Mathlib/CategoryTheory/Topos/Basic.lean`, which currently includes: * The definition of an elementary topos. * Proof that the power object map is a functor * Theorem about pullbacks of characterstic maps Subobject classifiers, which are used in the definition, have already been defined in `CategoryTheory/Topos/Classifier.lean` Work in progress: further formalization of the section is planned. Questions: * Should the definition of power objects be separated into its own file/module, perhaps under `CategoryTheory/Topos/PowerObject.lean`? * Is the notation `P` / `P_morph` / `P_functor` for the power object functor on objects / morphisms / total acceptable? * Should the comments and docstrings rather use the notation from the book, where `g ∘ f` denotes arrow composition from righ to left, or the Lean variant `f ≫ g`? Klaus Gy klausgy@gmail.com --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-category-theory new-contributor	401/66	Mathlib.lean,Mathlib/CategoryTheory/Closed/PowerObjects.lean,Mathlib/CategoryTheory/Limits/Shapes/BinaryProducts.lean,Mathlib/CategoryTheory/Limits/Shapes/Equalizers.lean,Mathlib/CategoryTheory/Limits/Shapes/Pullback/CommSq.lean,Mathlib/CategoryTheory/Limits/Shapes/Pullback/Equalizer.lean,Mathlib/CategoryTheory/Monoidal/Cartesian/Basic.lean,Mathlib/CategoryTheory/Subobject/Basic.lean,Mathlib/CategoryTheory/Topos/Classifier.lean	9	17	['fweth', 'github-actions', 'joelriou', 'leanprover-community-bot-assistant', 'mathlib4-merge-conflict-bot']	joelriou assignee:joelriou	195-25432 6 months ago	224-78451 224 days ago	62-6664 62 days
27155	Pjotr5 author:Pjotr5	feat: Shearer's bound on the independence number of triangle free graphs	I added the file IndependenceNumber.lean to the Mathlib.Combinatorics.SimpleGraph.Triangle folder. It contains a proof of a theorem by Shearer on the independence number of triangle-free graphs . I was told this might be useful to add to Mathlib a Zullip thread linked [here](https://leanprover.zulipchat.com/#narrow/channel/217875-Is-there-code-for-X.3F/topic/Convexity.20of.20a.20specific.20function/with/510469526). I tried to comply as much as I could with the Mathlib style guide, but I realise that there is probably still a significant amount of editing to be done. For one thing: there are probably some lemmas and theorems in there that might be better suited in other files, but since this is my first PR I though I would all put it in one file before starting to edit a bunch of files. I was also advised to split up the file into multiple smaller PRs, but since everything is basically serving this one proof I could not really find a natural way to do that. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-combinatorics new-contributor	1266/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Triangle/IndependenceNumber.lean	2	10	['Pjotr5', 'github-actions', 'grunweg', 'mathlib4-merge-conflict-bot']	nobody	195-25395 6 months ago	unknown	unknown
27753	YunkaiZhang233 author:YunkaiZhang233	feat(CategoryTheory): implemented proofs for factorisation categories being equivalent to iterated comma categories in two ways	--- Completed one of the tasks in TODOs, shown and implemented the details for (X/C)/f ≌ Factorisation f ≌ f/(C/Y). This is migrated from my previous PR #22390 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-category-theory new-contributor	70/1	Mathlib/CategoryTheory/Category/Factorisation.lean	1	13	['YunkaiZhang233', 'b-mehta', 'github-actions', 'mathlib4-merge-conflict-bot', 'robin-carlier']	nobody	195-25240 6 months ago	unknown	unknown
27850	fyqing author:fyqing	feat: 0-dimensional manifolds are discrete and countable	This is the converse direction of the classification of 0-dimensional manifolds. The other direction was shown in #22105. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-differential-geometry new-contributor	80/0	Mathlib.lean,Mathlib/Geometry/Manifold/ZeroDim.lean	2	14	['fyqing', 'github-actions', 'grunweg', 'mathlib4-merge-conflict-bot', 'tb65536']	grunweg assignee:grunweg	195-25238 6 months ago	304-57465 304 days ago	0-5228 1 hour
28125	nonisomorphiclinearmap author:nonisomorphiclinearmap	feat(Combinatorics): basic definition of simplicial complexes	This PR introduces the basic definition of a finite (abstract) simplicial complex, located in Mathlib/Combinatorics/SimplicialComplex/Basic.lean. --- This is our first contribution to mathlib. This work was done as part of the Fields Institute Summer Undergraduate Program on formalization in topological combinatorics. Eventually, we aim to formalize Lovasz's proof of the Kneser Conjecture and this is a small stepping stone in that direction. Some other commits will shortly depend on this one. We would like to acknowledge the Fields Institute for Research in Mathematical Sciences for their sponsorship. We would also like to thank our supervisors, Professor Chris Kapulkin and Mr. Daniel Carranza, for their guidance and support throughout this project. We would also like to thank our group members Tom Lindquist and Quang Minh Nguyen for our fruitful discussions.	merge-conflict t-combinatorics new-contributor	374/0	Mathlib.lean,Mathlib/Combinatorics/SimplicialComplex/Basic.lean,Mathlib/Combinatorics/SimplicialComplex/Category.lean,Mathlib/Combinatorics/SimplicialComplex/FacePoset.lean,Mathlib/Combinatorics/SimplicialComplex/Hom.lean	5	2	['github-actions', 'mathlib4-merge-conflict-bot']	awainverse assignee:awainverse	195-25106 6 months ago	195-25107 195 days ago	99-49043 99 days
28530	nonisomorphiclinearmap author:nonisomorphiclinearmap	feat(Combinatorics/SimplicialComplex/Topology): add standard simplices and geometric realisation (colimit + functoriality)	Introduce the standard simplex on a finite vertex set and build the geometric realisation \|X\| of a simplicial complex. Prove that \|X\| is the colimit of the face diagram δ_X : X.faces ⥤ TopCat, and define the induced map on realisations \|φ\| : \|X\| ⟶ \|Y\| for a simplicial map φ. Show that the abstract map from colimit functoriality agrees with the concrete push-forward of barycentric coordinates. Package these into a functor SimplicialComplexCat ⥤ TopCat. --- This is our first contribution to mathlib. This work was done as part of the Fields Institute Summer Undergraduate Program on formalization in topological combinatorics. Eventually, we aim to formalize Lovasz's proof of the Kneser Conjecture and this lays the groundwork to do this. We would like to acknowledge the Fields Institute for Research in Mathematical Sciences for their sponsorship. We would also like to thank our supervisors, Professor Chris Kapulkin and Mr. Daniel Carranza, for their guidance and support throughout this project. I would also like to thank our group members Sebastian Kumar, Tom Lindquist and Quang Minh Nguyen for our fruitful discussions. - [ ] depends on: #28125	merge-conflict blocked-by-other-PR t-combinatorics new-contributor	1826/0	Mathlib.lean,Mathlib/Combinatorics/SimplicialComplex/Basic.lean,Mathlib/Combinatorics/SimplicialComplex/Category.lean,Mathlib/Combinatorics/SimplicialComplex/FacePoset.lean,Mathlib/Combinatorics/SimplicialComplex/Hom.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/GeomReal/Basic.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/GeomReal/Colimit.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/GeomReal/Diagram.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/GeomReal/Functor.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/GeomReal/Map.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/Simplex.lean,Mathlib/Combinatorics/SimplicialComplex/Topology/SimplexMap.lean	12	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	195-25092 6 months ago	unknown	unknown
28871	JaafarTanoukhi author:JaafarTanoukhi	feat(Combinatorics/Digraph): Tournaments	Define orientations and tournaments. Related to #26771. Co-authored-by: Rida Hamadani --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-combinatorics new-contributor	62/0	Mathlib.lean,Mathlib/Combinatorics/Digraph/Orientation.lean,Mathlib/Combinatorics/Digraph/Tournament.lean	3	6	['JaafarTanoukhi', 'Rida-Hamadani', 'SnirBroshi', 'github-actions', 'mathlib4-merge-conflict-bot']	kmill assignee:kmill	195-24953 6 months ago	195-24954 195 days ago	55-54848 55 days
29947	JaafarTanoukhi author:JaafarTanoukhi	feat(Combinatorics/Digraph): Maps	Ported `SimpleGraph/Maps.lean` to `Digraph/Maps.lean` for future PRs related to issue #[26771](https://github.com/leanprover-community/mathlib4/issues/26771) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-combinatorics new-contributor	476/0	Mathlib.lean,Mathlib/Combinatorics/Digraph/Maps.lean	2	2	['github-actions', 'mathlib4-merge-conflict-bot']	awainverse assignee:awainverse	195-24319 6 months ago	195-24320 195 days ago	54-82658 54 days
14704	Command-Master author:Command-Master	feat(FieldTheory): define typeclass for simple extensions, and prove some properties	Define `SimpleExtension F K`, which says that `K` is a simple field extension of `F`, and show that together with transcendentality it implies `IsFractionRing F[X] K`. --- - [x] depends on: #14710 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-algebra new-contributor merge-conflict awaiting-author label:t-algebra$	120/0	Mathlib.lean,Mathlib/FieldTheory/SimpleExtension.lean	2	19	['Command-Master', 'acmepjz', 'github-actions', 'leanprover-community-mathlib4-bot', 'mathlib4-merge-conflict-bot', 'tb65536']	nobody	195-21151 6 months ago	unknown	unknown
31590	SuccessMoses author:SuccessMoses	chore: tag `commutatorElement_def` with `simp`	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-algebra new-contributor merge-conflict label:t-algebra$	1/0	Mathlib/Algebra/Group/Commutator.lean	1	3	['github-actions', 'grunweg', 'mathlib-merge-conflicts']	nobody	194-85426 6 months ago	unknown	unknown
11021	jstoobysmith author:jstoobysmith	feat(AlgebraicTopology): add join of augmented SSets	This pull-request adds the definition of the join of augmented SSets defined as contravariant functors from `WithInitial SimplexCategory` to `Type u`. In addition it shows that the join of two standard augmented SSets is again an augmented SSets. From this the definition of the join of simplicial sets should follow easily. To aid the above theory, an api for `WithInitial SimplexCategory` has been created, with the notion of the `join` and `split` (forming a sort of inverse to join) of objects in this category are defined. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP t-algebraic-topology new-contributor	2137/1	.gitignore,Mathlib.lean,Mathlib/AlgebraicTopology/Join.lean,Mathlib/AlgebraicTopology/SimplexCategory.lean,Mathlib/AlgebraicTopology/SimplexCategoryWithInitial.lean,Mathlib/AlgebraicTopology/SimplicialSet.lean	6	47	['github-actions', 'jcommelin']	nobody	194-84567 6 months ago	unknown	unknown
18626	hannahfechtner author:hannahfechtner	feat: define Artin braid groups	Define the Artin braid group on infinitely many strands. Includes a toGroup function which defines a function out of the braid group to any other group (given a function which satisfies the braid relations) (more to come in this file; next up: Artin braid groups on finitely many strands) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-algebra new-contributor label:t-algebra$	91/0	Mathlib.lean,Mathlib/GroupTheory/SpecificGroups/BraidGroup/Basic.lean	2	22	['github-actions', 'hannahfechtner', 'jcommelin', 'joelriou']	nobody	194-84414 6 months ago	unknown	unknown
20029	FrederickPu author:FrederickPu	feat(Tactic/simps): allow for Config attributes to be set directly	Allow for Config attributes to be set directly when using initialize_simp_projection as per issue #19895 Basically modified initialize_simp_projection so that the user has the option of specifying a tuple of config option values. Ex: ``` initialize_simp_projection MulEquiv (toFun → apply, invFun → symm_apply) (fullyApplied := false) ``` These config options are then converted into projections. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP new-contributor t-meta	34/4	Mathlib/Tactic/Simps/Basic.lean	1	11	['FrederickPu', 'YaelDillies', 'fpvandoorn', 'github-actions', 'leanprover-community-bot-assistant']	nobody	194-84351 6 months ago	unknown	unknown
21269	658060 author:658060	feat(CategoryTheory/Topos): basic definitions and results in topos theory	This code contains basic definitions and results in topos theory, including the definition of a subobject classifier, power objects, and topoi. It is proved that every topos has exponential objects, i.e. "internal homs". The mathematical content follows chapter IV sections 1-2 of Mac Lane and Moerdijk's text "Sheaves in Geometry and Logic". --- - [x] depends on: #21281 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-category-theory new-contributor merge-conflict awaiting-author	1269/0	Mathlib.lean,Mathlib/CategoryTheory/Topos/Basic.lean,Mathlib/CategoryTheory/Topos/Classifier.lean,Mathlib/CategoryTheory/Topos/Exponentials.lean,Mathlib/CategoryTheory/Topos/Power.lean	5	10	['658060', 'gio256', 'github-actions', 'joelriou', 'mathlib4-dependent-issues-bot']	nobody	194-84324 6 months ago	unknown	unknown
23990	robertmaxton42 author:robertmaxton42	feat(Types.Colimits): Quot is functorial and colimitEquivQuot is natural	Add `Functor.quotFunctor` to parallel `Functor.sectionsFunctor`, witnessing that `Quot` is functorial; add `colimNatIsoQuotFunctor` to parallel `limNatIsoSectionsFunctor`, witnessing that `colimitEquivQuot` is natural in the diagram $F$. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-category-theory new-contributor	33/0	Mathlib/CategoryTheory/Limits/Types/Colimits.lean	1	5	['github-actions', 'joelriou', 'leanprover-community-bot-assistant', 'robertmaxton42']	nobody	194-84207 6 months ago	unknown	unknown
27991	sinianluoye author:sinianluoye	feat(Rat): add Rat.den_eq_of_add_den_eq_one and its dependent lemmas	```lean4 example {q r : ℚ} (h : (q + r).den = 1) : q.den = r.den := by ``` It is so simple, but I couldn't find it in current mathlib repo. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-data new-contributor	22/0	Mathlib/Data/Rat/Lemmas.lean	1	33	['github-actions', 'kim-em', 'mathlib-bors', 'pechersky', 'sinianluoye', 'themathqueen']	pechersky assignee:pechersky	194-83890 6 months ago	226-21084 226 days ago	74-28583 74 days
28215	5hv5hvnk author:5hv5hvnk	feat: strong and Weak connectivity for Digraphs	strong and weak connectivity in Digraphs --- Should resolve a part of issue #26771 Main additions in the PR: 1. Walks in Digraphs (Walk.lean) - Basic walk structure with start and end vertices - Support for walk operations: append, reverse, length - Support functions: getVert, copy, support 2. Walk Decompositions (WalkDecomp.lean) - takeUntil and dropUntil functions to split walks - rotate operation for loop walks - Theorems relating to walk decomposition properties 3. Subgraphs (subgraph.lean) - Subgraph structure for digraphs - Induced and spanning subgraph predicates - Lattice structure (sup, inf, top, bot) - Coercion to standalone digraphs 4. Paths (Paths.lean) - Trail, Path, Circuit, Cycle definitions - Path structure with no repeating vertices - Theorems relating different path types - Basic connectivity definitions (reachable, weakly/strongly connected) 5. Connectivity (Connected.lean) - Reachability relations and properties - Strong and weak connectivity definitions - Connected component types: - StronglyConnectedComponent - WeaklyConnectedComponent - ConnectedComponent - Component properties and equivalence relations --> [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP new-contributor merge-conflict awaiting-author t-combinatorics	1266/0	Mathlib.lean,Mathlib/Combinatorics/Digraph/Connected.lean,Mathlib/Combinatorics/Digraph/Paths.lean,Mathlib/Combinatorics/Digraph/Subgraph.lean,Mathlib/Combinatorics/Digraph/Walk.lean,Mathlib/Combinatorics/Digraph/WalkDecomp.lean	6	4	['github-actions', 'grunweg', 'mathlib4-merge-conflict-bot']	nobody	194-83869 6 months ago	unknown	unknown
29574	JarodAlper author:JarodAlper	feat: regular local rings are domains	We have added three new files in Mathlib/RingTheory/LocalRing * EmbeddingDimension.lean * LocalRingDimension.lean * RegularLocalRings.lean We have added two lemmas and an instance in Mathlib/RingTheory/LocalRing/RingHom/Basic.lean This work was done by Jarod Alper and Brian Nugent. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-ring-theory new-contributor	910/3	Mathlib.lean,Mathlib/RingTheory/LocalRing/EmbeddingDimension.lean,Mathlib/RingTheory/LocalRing/LocalRingDimension.lean,Mathlib/RingTheory/LocalRing/RegularLocalRings.lean,Mathlib/RingTheory/LocalRing/RingHom/Basic.lean,lake-manifest.json	6	2	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	194-83758 6 months ago	unknown	unknown
28718	imbrem author:imbrem	feat: class for chosen finite coproducts	Added basic `ChosenFiniteCoproducts` class, and started porting some of the lemmas about `ChosenFiniteProducts` suitably translated --- This, combined with #20182 modified to use chosen finite coproducts and premonoidal categories (#21488), should be enough for me to formalize strong Elgot categories, and hence a lot of categorical iteration theory for my PhD thesis. Re-done from #21603 to deal with changes in #24399 and #24390 Eventually, if we really want to harmonize approaches, we could introduce an `AddMonoidalCategory` struct and do the analogous to #24399 and #24390 for additive monoidal structure, but that seems like a massive overcomplication for now. It would allow formalizing fun things like rig categories, though. - [ ] depends on: #30150	blocked-by-other-PR t-category-theory new-contributor merge-conflict awaiting-author	290/0	Mathlib.lean,Mathlib/CategoryTheory/ChosenFiniteCoproducts.lean	2	9	['YaelDillies', 'github-actions', 'imbrem', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'robin-carlier']	nobody	194-83670 6 months ago	unknown	unknown
26765	KiringYJ author:KiringYJ	feat(MeasureTheory/PiSystem): add π-λ theorem and SetLike instance	Add two small features to `MeasureTheory/PiSystem`: 1. SetLike instance `instance : SetLike (DynkinSystem α) (Set α)` This lets us write `s ⊆ d` and `t ∈ d` for a DynkinSystem `d`, matching usual mathlib style. 2. `DynkinSystem.pi_lambda` lemma Classical π‑λ theorem: if a π‑system `s` is contained in a Dynkin system `d`, every set measurable for `σ(s)` is also in `d`. Currently, mathlib exposes this result only indirectly (e.g. via `generateFrom_eq`). Although logically equivalent, it is not obvious at first glance that those lemmas are the π‑λ theorem. The new lemma states the result in its familiar textbook form, so users can recognise and cite it immediately. Both pieces are under 10 lines, term‑mode only, and do not modify existing APIs. No breaking changes. No dependencies.	awaiting-author t-measure-probability new-contributor	13/0	Mathlib/MeasureTheory/PiSystem.lean	1	14	['EtienneC30', 'KiringYJ', 'dagurtomas', 'github-actions', 'ocfnash']	RemyDegenne assignee:RemyDegenne	194-70066 6 months ago	194-70066 194 days ago	135-36074 135 days
30637	strihanje01 author:strihanje01	feat(Combinatorics/SetFamily/Lindstrom): Lindstrom's theorem for subfamilies with equal unions	add Lindstrom's theorem and its strengthening for equal intersections --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	209/0	Mathlib/Combinatorics/SetFamily/Lindstrom.lean	1	2	['github-actions', 'mathlib4-merge-conflict-bot']	b-mehta assignee:b-mehta	192-5815 6 months ago	195-23974 195 days ago	31-46100 31 days
32169	saodimao20 author:saodimao20	feat: add convolution_comp_add_right	This PR adds a lemma `convolution_comp_translation_right` showing that convolution commutes with translation on the right operand. Specifically, it proves that for an additive commutative group $G$, the convolution of a function $f$ with a translated function $x \mapsto g(a + x)$ is equal to the convolution of $f$ and $g$ evaluated at $x + a$. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis new-contributor awaiting-author	14/0	Mathlib/Analysis/Convolution.lean	1	3	['github-actions', 'urkud']	nobody	186-26237 6 months ago	unknown	unknown
32126	nielsvoss author:nielsvoss	feat(Analysis/Normed/Operator): definition of singular values for linear maps	This PR defines a generalization of singular values, the approximation numbers, for continuous linear maps between normed vector spaces. It proves basic lemmas about the approximation numbers and shows that for finite-dimensional vector spaces, the approximation numbers coincide with the standard definition of singular values. See the discussion on Zulip: https://leanprover.zulipchat.com/#narrow/channel/217875-Is-there-code-for-X.3F/topic/Singular.20Value.20Decomposition/with/558914024 Co-authored-by: Arnav Mehta Co-authored-by: Rawad Kansoh --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-analysis new-contributor	331/0	Mathlib/Analysis/Normed/Operator/SingularValues.lean	1	2	['github-actions', 'nielsvoss']	nobody	185-63778 6 months ago	unknown	unknown
30525	515801431 author:515801431	feat(Mathlib/Combinatorics/Enumerative/Polya): Add Polya Counting	This PR introduces basic definitions and results about colorings under permutation group actions. A coloring is defined as a function X → Y, and the permutation group Equiv.Perm X acts on colorings by precomposition: (g • c) x = c (g⁻¹ • x) This formalizes the natural action of relabeling the elements of X. Main definitions MulAction (Equiv.Perm X) (X → Y): The action of the permutation group on colorings via precomposition. coloringEquiv (c₁ c₂ : X → Y) : Prop: Two colorings are equivalent if they lie in the same orbit under this action, i.e. ∃ f : Equiv.Perm X, f • c₁ = c₂. Main results smul_eq_iff_mem_stabilizer: Characterizes when two group actions on the same coloring are equal, showing that g • c = f • c ↔ f⁻¹ * g ∈ stabilizer c. coloringEquiv_equivalence: Proves that coloringEquiv defines an equivalence relation on X → Y. orbit_size_eq_index: Reformulates the orbit–stabilizer theorem in the context of colorings: \|orbit c\| = \|Perm X\| / \|stabilizer c\| Motivation These results provide foundational infrastructure for studying Burnside’s lemma and Pólya’s enumeration theorem in Mathlib, where the enumeration of distinct colorings up to symmetry plays a central role.	t-combinatorics new-contributor awaiting-author merge-conflict	113/0	Mathlib.lean,Mathlib/Combinatorics/Enumerative/Polya.lean	2	8	['IvanRenison', 'alreadydone', 'github-actions', 'mathlib4-merge-conflict-bot']	awainverse assignee:awainverse	178-71376 5 months ago	187-28519 187 days ago	39-43496 39 days
31113	515801431 author:515801431	feat(Mathlib/Combinatorics/Enumerative/Polya.lean): Add additional theorem in `Polya.lean`	--- - [ ] depends on: #30525 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor blocked-by-other-PR merge-conflict	302/0	Mathlib.lean,Mathlib/Combinatorics/Enumerative/Polya.lean	2	4	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	b-mehta assignee:b-mehta	178-71252 5 months ago	188-7278 188 days ago	16-76595 16 days
24441	MrSumato author:MrSumato	feat(Data/List): add Lyndon-Schutzenberger theorem on list commutativity	Add Lyndon-Schutzenberger theorem on list commutativity. Included definition for List.repeatSelf that returns list repeated n times. --- This is my first mathlib PR, so any comments are highly appreciated. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author t-data new-contributor	129/1	Mathlib.lean,Mathlib/Data/List/Commutativity.lean,Mathlib/Data/List/Defs.lean,Mathlib/Data/List/Lemmas.lean	4	38	['MrSumato', 'github-actions', 'grunweg', 'madvorak', 'mathlib4-merge-conflict-bot', 'plp127']	grunweg assignee:grunweg	178-66854 5 months ago	unknown	unknown
31147	daefigueroa author:daefigueroa	feat(Dynamics): point transitive monoid actions and transitive points	We define point transitivity for a monoid action on a topological space and define the set of transitive points. We add some basic lemmas and implications between topological transitivity and point transitivity. --- - [x] depends on: #28001 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-dynamics new-contributor awaiting-author	114/6	Mathlib/Dynamics/Transitive.lean	1	6	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'sgouezel']	sgouezel assignee:sgouezel	176-5687 5 months ago	176-5687 176 days ago	18-34774 18 days
31987	saodimao20 author:saodimao20	feat: add monotonicity and relation lemmas for mgf and cgf	Add two lemmas about moment-generating and cumulant-generating functions: - `mgf_mono_in_t_of_nonneg`: For nonnegative random variables, the mgf is monotone in the parameter `t` - `cgf_zero_of_mgf_one`: The cgf equals zero iff the mgf equals one These lemmas are useful for studying properties of mgf and cgf in probability theory. Contributed by sequential-intelligence-lab(SIL), University of Virginia --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-measure-probability new-contributor awaiting-author	21/0	Mathlib/Probability/Moments/Basic.lean	1	5	['DavidLedvinka', 'github-actions']	RemyDegenne assignee:RemyDegenne	169-84193 5 months ago	unknown	unknown
32938	0xTerencePrime author:0xTerencePrime	feat(Order/LocallyFinite): prove DenselyOrdered and LocallyFiniteOrder are incompatible	## Summary This PR proves that a nontrivial densely ordered linear order cannot be locally finite. ## Main results * `not_locallyFiniteOrder`: A densely ordered locally finite linear order must be subsingleton. * `not_locallyFiniteOrder_of_nontrivial`: The main theorem - incompatibility of the two properties. Note: This implementation imports `Mathlib.Order.Interval.Set.Infinite` to reuse the existing `Set.Icc_infinite` theorem, ensuring standard library consistency. ## Mathematical content The key insight is that in a densely ordered type, we can always find a new element between any two distinct elements. This means any nontrivial interval contains infinitely many elements. However, `LocallyFiniteOrder` requires intervals to be finite. This contradiction implies that such a type cannot exist (unless it is trivial). ## Motivation This resolves a TODO mentioned in #7987 (Data/Finset/LocallyFinite entry). ## Verification - [x] `lake build Mathlib.Order.LocallyFinite.Basic` passes - [x] `lake exe runLinter Mathlib.Order.LocallyFinite.Basic` passes	t-order new-contributor awaiting-author	28/0	Mathlib/Order/Interval/Finset/Basic.lean	1	10	['0xTerencePrime', 'CoolRmal', 'github-actions', 'jcommelin', 'plp127']	nobody	165-21195 5 months ago	165-21235 165 days ago	3-6032 3 days
32698	farruhx author:farruhx	feat(List): add aesop / simp annotations to selected lemmas for improved automation	This PR adds `@[aesop safe]` and `@[simp]` annotations to a set of List lemmas whose proofs are routine and benefit from standardized automation. No statements or definitions are changed; only proof annotations are added. The lemmas updated in this PR are: * `or_exists_of_exists_mem_cons` * `append_subset_of_subset_of_subset` * `map_subset_iff` * `append_eq_has_append` * `append_right_injective` * `append_left_injective` * `reverse_surjective` * `reverse_bijective` * `mem_getLast?_append_of_mem_getLast?` * `mem_dropLast_of_mem_of_ne_getLast` * `idxOf_eq_length_iff` * `idxOf_append_of_mem` * `length_eraseP_add_one` The goal is to make these commonly used lemmas easier for `aesop`-based automation to resolve, while avoiding any interference with simp-normal-form lemmas or canonical rewrite rules. There are no API changes and no new theorems—only improved automation behavior.	t-data new-contributor awaiting-author	18/1	Mathlib/Data/List/Basic.lean	1	8	['artie2000', 'euprunin', 'farruhx', 'github-actions']	pechersky assignee:pechersky	164-55964 5 months ago	164-55964 164 days ago	7-30937 7 days
27817	zhuyizheng author:zhuyizheng	feat: add IMO2025P1	Add a solution to IMO2025P1, the original problem statement from https://github.com/jsm28/IMOLean --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	IMO awaiting-author new-contributor merge-conflict	1310/0	Archive.lean,Archive/Imo/Imo2025Q1.lean	2	9	['github-actions', 'kim-em', 'mathlib4-merge-conflict-bot', 'zhuyizheng']	dwrensha assignee:dwrensha	164-1761 5 months ago	223-52729 223 days ago	54-72325 54 days
33218	Blackfeather007 author:Blackfeather007	feat(Algebra): Define the associated graded ring to filtered ring	Define the associated graded ring to a filtered ring. --- - [ ] depends on: #33217 migrated from https://github.com/leanprover-community/mathlib4/pull/26858	t-ring-theory new-contributor blocked-by-other-PR	450/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean	2	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-34426 5 months ago	unknown	unknown
33219	Blackfeather007 author:Blackfeather007	feat(Algebra): Define associated graded algebra	Define the associated graded algebra of a filtered algebra, constructed from a special case of associated graded ring. --- - [ ] depends on: #33218 migrated from #26859	t-ring-theory new-contributor blocked-by-other-PR	563/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean	2	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-34318 5 months ago	unknown	unknown
33220	Blackfeather007 author:Blackfeather007	feat(Algebra): Define associated graded module	Define the associated graded module to a filtered module. --- - [ ] depends on: #33218 migrated from #26860	t-ring-theory new-contributor blocked-by-other-PR	669/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean	2	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-34234 5 months ago	unknown	unknown
33227	Blackfeather007 author:Blackfeather007	feat(Algebra): exact of associated graded exact	We proved that a chain complex is exact if its associated graded complex is exact. Co-authored-by: Huanyu Zheng @Yu-Misaka [suzuka@misaka-yu.com](mailto:suzuka@misaka-yu.com) Co-authored-by: Yi Yuan @yuanyi-350 [kysyy1@126.com](mailto:kysyy1@126.com) Co-authored-by: Weichen Jiao @AlbertJ-314 [albertjiao314@gmail.com](mailto:albertjiao314@gmail.com) --- - [ ] depends on: #33226 migrated from #26869	t-ring-theory new-contributor blocked-by-other-PR	728/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean,Mathlib/RingTheory/FilteredAlgebra/Exactness.lean,Mathlib/RingTheory/FilteredAlgebra/FilteredHom.lean	4	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-31906 5 months ago	161-31907 161 days ago	0-206 3 minutes
33226	Blackfeather007 author:Blackfeather007	feat(Algebra): associated graded exact of exact and strict	In this file, we define the concept of exhaustive filtrations. We also prove a AssociatedGradedRingHom sequence is exact iff each GradedPieceHom is exact. And when a sequence is strict exact, the corresponding AssociatedGradedRingHom sequence is also exact. Co-authored-by: Huanyu Zheng @Yu-Misaka [suzuka@misaka-yu.com](mailto:suzuka@misaka-yu.com) Co-authored-by: Yi Yuan @yuanyi-350 [kysyy1@126.com](mailto:kysyy1@126.com) Co-authored-by: Weichen Jiao @AlbertJ-314 [albertjiao314@gmail.com](mailto:albertjiao314@gmail.com) --- - [ ] depends on: #33222 migrated from #26868	t-ring-theory new-contributor blocked-by-other-PR	529/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean,Mathlib/RingTheory/FilteredAlgebra/Exactness.lean,Mathlib/RingTheory/FilteredAlgebra/FilteredHom.lean	4	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-31904 5 months ago	161-31905 161 days ago	0-1284 21 minutes
33225	Blackfeather007 author:Blackfeather007	feat(Algebra): filtered module hom	In this PR we defined the filtered semi-linear map for filtered module and the associated graded module hom. --- - [ ] depends on: #33220 - [ ] depends on: #33223 migrated from #26867	t-ring-theory new-contributor blocked-by-other-PR	1205/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean,Mathlib/RingTheory/FilteredAlgebra/FilteredHom.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-31903 5 months ago	unknown	unknown
33224	Blackfeather007 author:Blackfeather007	feat(Algebra): define filtered alghom	In this PR, we define the filtered algebra homomorphisms on algebras and prove some basic properties of them. --- - [ ] depends on: #33219 - [ ] depends on: #33223 migrated from #26863	t-ring-theory new-contributor blocked-by-other-PR	1055/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean,Mathlib/RingTheory/FilteredAlgebra/FilteredHom.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-31901 5 months ago	161-31902 161 days ago	0-978 16 minutes
33223	Blackfeather007 author:Blackfeather007	feat(Algebra): define filtered ring homomorphism	In this PR, we define the filtered ring morphisms on rings and prove some basic properties of them. Co-authored-by: Huanyu Zheng @Yu-Misaka [suzuka@misaka-yu.com](mailto:suzuka@misaka-yu.com) Co-authored-by: Yi Yuan @yuanyi-350 [kysyy1@126.com](mailto:kysyy1@126.com) Co-authored-by: Weichen Jiao @AlbertJ-314 [albertjiao314@gmail.com](mailto:albertjiao314@gmail.com) --- - [ ] depends on: #33218 - [ ] depends on: #33222 migrated from #26862	t-ring-theory new-contributor blocked-by-other-PR	824/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean,Mathlib/RingTheory/FilteredAlgebra/FilteredHom.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-31898 5 months ago	161-31901 161 days ago	0-1162 19 minutes
33222	Blackfeather007 author:Blackfeather007	feat(Algebra): define filtered add group hom	In this file we define filtered hom and the corresponding associated graded hom for abelian groups. Co-authored-by: Huanyu Zheng @Yu-Misaka [suzuka@misaka-yu.com](mailto:suzuka@misaka-yu.com) Co-authored-by: Yi Yuan @yuanyi-350 [kysyy1@126.com](mailto:kysyy1@126.com) Co-authored-by: Weichen Jiao @AlbertJ-314 [albertjiao314@gmail.com](mailto:albertjiao314@gmail.com) --- - [ ] depends on: #33217 migrated from #26861	new-contributor t-ring-theory blocked-by-other-PR	368/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean,Mathlib/RingTheory/FilteredAlgebra/FilteredHom.lean	3	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	161-31897 5 months ago	161-31898 161 days ago	0-2236 37 minutes
32264	jjtowery author:jjtowery	feat(Bicategory): add lax slice bicategory	--- In this PR, I define the lax slice bicategory for a lax functor over an object. I also give the change of slice strict pseudofunctor. These are from Section 7.1 of Johnson & Yau and are essential for their Whitehead theorem for bicategories (lax functor biequivalence iff essentially surjective, essentially full, and fully faithful), which I'd like to prove at some point. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-category-theory new-contributor awaiting-author	527/0	Mathlib.lean,Mathlib/CategoryTheory/Bicategory/LaxSlice.lean	2	12	['dagurtomas', 'github-actions', 'jjtowery', 'robin-carlier']	dagurtomas assignee:dagurtomas	157-60383 5 months ago	180-63840 180 days ago	3-47878 3 days
32960	dleijnse author:dleijnse	feat(FieldTheory): adjoin pth roots	For a field `k` of exponential characteristic `p` and a subset `S` of `k`, we define the extension of `k` obtained by adjoining all `p`-th roots of elements of `S`. We prove that this is a purely inseparable extension, and provide some basic API. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author label:t-algebra$	131/0	Mathlib.lean,Mathlib/FieldTheory/PurelyInseparable/AdjoinPthRoots.lean	2	13	['artie2000', 'chrisflav', 'dleijnse', 'erdOne', 'github-actions', 'leanprover-radar']	erdOne assignee:erdOne	156-77035 5 months ago	156-77035 156 days ago	9-18892 9 days
33163	Aaron1011 author:Aaron1011	feat: prove subgroup of (M -> Z) is finitely generated	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory new-contributor awaiting-author	5/0	Mathlib/RingTheory/DedekindDomain/Dvr.lean	1	2	['erdOne', 'github-actions']	alreadydone assignee:alreadydone	156-69985 5 months ago	156-69985 156 days ago	5-80574 5 days
33133	0xTerencePrime author:0xTerencePrime	feat(Algebra/Group/Center): add Decidable (IsMulCentral a) instance	This PR adds a `Decidable` instance for `IsMulCentral a`. ### Summary The structure `IsMulCentral` was missing a `Decidable` instance. This PR provides the instance by leveraging `isMulCentral_iff`, enabling decidability for both multiplicative and additive (via `to_additive`) structures. ### Verification - `lake build Mathlib.Algebra.Group.Center` passed. - `lake exe runLinter Mathlib.Algebra.Group.Center` passed.	t-algebra new-contributor awaiting-author label:t-algebra$	7/0	Mathlib/Algebra/Group/Center.lean	1	3	['github-actions', 'robin-carlier']	ocfnash assignee:ocfnash	151-11776 5 months ago	unknown	unknown
33502	MrQubo author:MrQubo	fix(Tactic/ProxyType): Pass params explicitly in proxy_equiv% implementation	Fix [#mathlib4 > `deriving Fintype` with Prop](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/.60deriving.20Fintype.60.20with.20Prop/with/566118621) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-meta WIP	12/2	Mathlib/Tactic/ProxyType.lean,MathlibTest/DeriveFintype.lean	2	7	['MrQubo', 'github-actions', 'kmill']	kmill assignee:kmill	149-65100 4 months ago	149-65101 149 days ago	0-59938 16 hours
17176	arulandu author:arulandu	feat: integrals and integrability with .re	Lemmas for swapping order of .re and integration/integrability. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict awaiting-author new-contributor t-measure-probability please-adopt	49/0	Mathlib/MeasureTheory/Function/L1Space.lean,Mathlib/MeasureTheory/Integral/IntegrableOn.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral.lean,Mathlib/MeasureTheory/Integral/SetIntegral.lean	4	32	['EtienneC30', 'arulandu', 'github-actions', 'loefflerd']	nobody	147-68098 4 months ago	unknown	unknown
33330	michael-novak-math author:michael-novak-math	feat: add arc-length reparametrization of parametrized curves	add new definitions of arc-length reparametrization and its corresponding parameter transformation and a theorem establishing the desired properties.	t-analysis new-contributor awaiting-author merge-conflict	311/0	Mathlib.lean,Mathlib/Analysis/Calculus/ArcLengthReparametrization.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/FundThmCalculus.lean,docs/references.bib	5	57	['SnirBroshi', 'github-actions', 'grunweg', 'j-loreaux', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot', 'michael-novak-math']	j-loreaux assignee:j-loreaux	145-49053 4 months ago	145-49054 145 days ago	6-69574 6 days
33756	dleijnse author:dleijnse	feat(FieldTheory): root of polynomial with p power coefficients	This PR proves the results in https://stacks.math.columbia.edu/tag/031V, which gives a criterion for a root of a polynomial over a field `k` of characteristic `p` to be a `p`-th power. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor label:t-algebra$	88/0	Mathlib.lean,Mathlib/FieldTheory/PthPowerCoeffPoly.lean	2	1	['github-actions']	nobody	145-198 4 months ago	unknown	unknown
33299	kingiler author:kingiler	feat: Add decidable membership for Interval	Implemented membership and corresponding decidable instance for `Interval`. Related [#mathlib4 > Proposal: Add decidable membership for Interval](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Proposal.3A.20Add.20decidable.20membership.20for.20Interval/with/565438009). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author new-contributor t-order	16/1	Mathlib/Order/Interval/Basic.lean	1	5	['Vierkantor', 'eric-wieser', 'github-actions', 'kingiler']	Vierkantor assignee:Vierkantor	144-78404 4 months ago	144-78404 144 days ago	13-42146 13 days
30142	shalliso author:shalliso	feat(Topology/Baire): define IsNonMeagre	non-meagre sets (also known as "of the second category") are worthy of their own definition and API. This was useful to me for formalizing a result of "automatic continuity", that is, a Baire-measurable homomorphism between Polish groups must be continuous. Simply working with the negation of IsMeagre quickly became cumbersome, and non-meagre sets have an important role in the study of Polish (e.g. locally compact) groups. From https://github.com/shalliso/automatic_continuity --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor merge-conflict awaiting-author	83/1	Mathlib/Topology/Baire/NonMeagre.lean,Mathlib/Topology/GDelta/Basic.lean	2	6	['github-actions', 'grunweg', 'mathlib4-merge-conflict-bot']	nobody	144-1688 4 months ago	unknown	unknown
32880	0xTerencePrime author:0xTerencePrime	feat(Analysis/Asymptotics): define subpolynomial growth	## Main definitions * `Asymptotics.IsSubpolynomial l f g`: A function `f` has subpolynomial growth with respect to `g` along filter `l` if `f = O(1 + ‖g‖^k)` for some natural `k`. ## Main results * `IsSubpolynomial.const`: Constant functions have subpolynomial growth * `IsSubpolynomial.id`: Identity has subpolynomial growth * `IsSubpolynomial.add`: Closure under addition * `IsSubpolynomial.neg`: Closure under negation * `IsSubpolynomial.sub`: Closure under subtraction * `IsSubpolynomial.mul`: Closure under multiplication * `IsSubpolynomial.pow`: Closure under powers * `isSubpolynomial_iff_one_add`: Equivalence with `(1 + ‖g‖)^k` formulation * `IsSubpolynomial.uniform`: Uniform bounds for finite families ## Implementation notes The definition uses `1 + ‖g‖^k` rather than `(1 + ‖g‖)^k` as the primary form, with the equivalence established in `isSubpolynomial_iff_one_add`. Four private auxiliary lemmas handle the key inequalities needed for closure proofs. Closes #32658	awaiting-author t-analysis new-contributor	185/0	Mathlib.lean,Mathlib/Analysis/Asymptotics/Subpolynomial.lean	2	29	['0xTerencePrime', 'ADedecker', 'github-actions', 'j-loreaux']	ADedecker assignee:ADedecker	140-71172 4 months ago	141-52630 141 days ago	22-14105 22 days
33948	anivegesana author:anivegesana	feat(Analysis/Normed/Algebra): matrix exponential of nilpotent matrix	Where the matrix exponential and nilpotent elements are defined, both the matrix exponential and the nilpotent element exponential. I had to add a different theorem for normed space exponential and the matrix exponential since the right instances wouldn't be synthesized. Help with golfing would be appreciated. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-analysis	34/0	Mathlib/Analysis/Normed/Algebra/Exponential.lean,Mathlib/Analysis/Normed/Algebra/MatrixExponential.lean	2	1	['github-actions']	nobody	139-35757 4 months ago	unknown	unknown
30391	rudynicolop author:rudynicolop	feat(Data/List): list splitting definitions and lemmas	This PR continues the work from #24395. Original PR: https://github.com/leanprover-community/mathlib4/pull/24395	t-data new-contributor awaiting-author	108/2	Mathlib/Data/List/Perm/Lattice.lean,Mathlib/Data/List/TakeDrop.lean	2	50	['BoltonBailey', 'IlPreteRosso', 'TwoFX', 'Vierkantor', 'github-actions', 'kckennylau', 'mathlib4-merge-conflict-bot', 'rudynicolop']	TwoFX assignee:TwoFX	137-3103 4 months ago	137-11625 137 days ago	91-73926 91 days
29282	Jlh18 author:Jlh18	feat(CategoryTheory): HasColimits instance on Grpd	Show that the category of groupoids has all small colimits, as a coreflective subcategory of `Cat`, which has all small colimits. The right adjoint of the forgetful functor is the core functor `CategoryTheory.Core.functor`. - [ ] depends on: #29283 [Core of a category as a functor] --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR new-contributor t-category-theory	140/4	Mathlib.lean,Mathlib/AlgebraicTopology/FundamentalGroupoid/InducedMaps.lean,Mathlib/CategoryTheory/Category/Grpd.lean,Mathlib/CategoryTheory/Core.lean,Mathlib/CategoryTheory/Groupoid/Grpd/Colimit.lean,Mathlib/CategoryTheory/Groupoid/Grpd/Core.lean	6	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	135-13183 4 months ago	unknown	unknown
32745	LTolDe author:LTolDe	feat(Topology/Algebra): add MulActionConst.lean	add Topology/Algebra/MulActionConst.lean introduce class `ContinuousSMulConst` for a scalar multiplication that is continuous in the first argument, in analogy to `ContinuousConstSMul` define `MulAction.ball x U` as the set `U • {x}` given `[SMul G X] (x : X) (U : Set G)` The lemmas shown here will be useful to prove the Effros Theorem, see [zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Effros.20Theorem/with/558712441). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author new-contributor t-topology	117/0	Mathlib.lean,Mathlib/Topology/Algebra/MulActionConst.lean	2	8	['LTolDe', 'github-actions', 'urkud']	nobody	133-85449 4 months ago	140-64979 140 days ago	16-32906 16 days
33478	anishrajeev author:anishrajeev	feat(ModelTheory): define a subset of the topology over complete types	Define a subset of the Stone Space over a language expanded with countably many constants. Define the proposition to indicate if a language is countable. The subset's density and openness is a future goal to prove (have a branch where it is almost finished), in pursuit of formalizing the proof of the Omitting Types Theorem via properties of Baire spaces. - [ ] depends on: #32215 - [ ] depends on: #32546	t-logic merge-conflict new-contributor blocked-by-other-PR	160/1	Mathlib.lean,Mathlib/ModelTheory/Topology/Types.lean,Mathlib/ModelTheory/Types.lean,Mathlib/Tactic/Linter/DirectoryDependency.lean	4	8	['NoneMore', 'anishrajeev', 'github-actions', 'mathlib-dependent-issues', 'mathlib4-merge-conflict-bot', 'tb65536']	nobody	132-78968 4 months ago	141-6392 141 days ago	9-59589 9 days
34141	gululu996-ui author:gululu996-ui	feat(Combinatorics/SimpleGraph/Acyclic): finite trees have at least two degree-one vertices	Add a lemma showing that a finite tree with at least two vertices has at least two vertices of degree 1. - Introduce a helper lemma `SimpleGraph.Connected.one_le_degree` for connected graphs on a nontrivial finite type. - Prove the leaf-count lower bound via the degree-sum identity and a counting argument. ---	awaiting-author new-contributor t-combinatorics	72/2	Mathlib/Combinatorics/SimpleGraph/Acyclic.lean	1	9	['IvanRenison', 'SnirBroshi', 'github-actions', 'vlad902']	nobody	130-82726 4 months ago	132-64162 132 days ago	0-53345 14 hours
29953	slashbade author:slashbade	feat: add reap for experiment	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor	40/3	Cache/IO.lean,Mathlib/Tactic/Common.lean,Mathlib/Tactic/Linter/DirectoryDependency.lean,lake-manifest.json,lakefile.lean	5	3	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	125-75251 4 months ago	unknown	unknown
31377	CoolRmal author:CoolRmal	feat: a series of smooth functions that converges (locally) uniformly is smooth	The main theorem is the proof that an infinite sum of $C^n$ functions on a one-dimensional domain which converges locally uniformly is $C^n$ and related results. This should be compared with [contDiff_tsum](https://leanprover-community.github.io/mathlib4_docs/Mathlib/Analysis/Calculus/SmoothSeries.html#contDiff_tsum) where the same result is proved for functions on an arbitrary domain but with a slightly stronger convergence assumption. The main motivation for this PR is the [#mathlib4 > Tychonov's Counterexample for the Heat Equation](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Tychonov's.20Counterexample.20for.20the.20Heat.20Equation/with/547367912). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor awaiting-author merge-conflict	110/18	Mathlib/Analysis/Calculus/SmoothSeries.lean,Mathlib/Analysis/SpecialFunctions/Trigonometric/Cotangent.lean,Mathlib/NumberTheory/ModularForms/EisensteinSeries/QExpansion.lean,Mathlib/Topology/Algebra/InfiniteSum/TsumUniformlyOn.lean,Mathlib/Topology/Algebra/InfiniteSum/UniformOn.lean	5	20	['CoolRmal', 'github-actions', 'mathlib4-merge-conflict-bot', 'ocfnash', 'sgouezel']	ocfnash assignee:ocfnash	124-64824 4 months ago	185-81789 185 days ago	8-12391 8 days
33031	chiyunhsu author:chiyunhsu	feat(Combinatorics/Enumerative/Partition): add combinatorial proof of Euler's partition theorem	The new file EulerComb.lean contains the combinatorial proof of Euler's partition theorem. The analytic proof of the theorem and its generalization of Glaisher's Theorem has already been formalized in [Glaisher.lean](https://github.com/leanprover-community/mathlib4/blob/master/Mathlib/Combinatorics/Enumerative/Partition/Glaisher.lean). The generalization of the combinatorial proof from this file to Glaisher's Theorem is within reach. --- Zulip discussion: [#mathlib4 > Glaisher’s Bijection on integer partitions](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Glaisher.E2.80.99s.20Bijection.20on.20integer.20partitions/with/570808111) [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor awaiting-zulip awaiting-author	531/0	Mathlib.lean,Mathlib/Combinatorics/Enumerative/Partition/EulerComb.lean	2	7	['chiyunhsu', 'dagurtomas', 'github-actions', 'tb65536', 'vihdzp']	b-mehta assignee:b-mehta	124-1945 4 months ago	124-1945 124 days ago	42-20793 42 days
34130	FlAmmmmING author:FlAmmmmING	feat(Combinatorics/SimpleGraph/Acyclic): Add new theorem `isTree_iff_uniqueShortest_path`	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-combinatorics new-contributor	28/1	Mathlib/Combinatorics/SimpleGraph/Acyclic.lean	1	9	['IvanRenison', 'github-actions', 'metakunt', 'vlad902']	nobody	123-24352 4 months ago	132-8367 132 days ago	0-21348 5 hours
34487	martinwintermath author:martinwintermath	feat(LinearAlgebra/SesquilinearForm): add instances for SeparatingLeft, SeparatingRight and Nondegenerate	Add typeclass instances for `Fact B.SeparatingLeft`, `Fact B.SeparatingRight`, `Fact B.Nondegenerate`: * inferring `Fact B.flip.SeparatingLeft` from `Fact B.SeparatingRight` and vice versa * inferring `Fact B.SeparatingLeft` and `Fact B.SeparatingRight` from `Fact B.Nondegenerate` * inferring `Fact B.SeparatingLeft` and `Fact B.Nondegenerate` for `.id` and `Dual.eval` * inferring `Fact B.Nondegenerate` from `B.IsPerfPair` I also updated `PointedCone.dual_univ` to demonstrate the usefulness of these additions. Note that I needed to add an import to `Cone/Dual.lean` which somehow imports cardinals. So I needed to remove cardinals from `assert_not_exists`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor large-import merge-conflict label:t-algebra$	67/12	Mathlib/Geometry/Convex/Cone/Dual.lean,Mathlib/LinearAlgebra/Dual/Lemmas.lean,Mathlib/LinearAlgebra/PerfectPairing/Basic.lean,Mathlib/LinearAlgebra/SesquilinearForm/Basic.lean	2	4	['github-actions', 'martinwintermath', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot']	joelriou assignee:joelriou	123-11006 4 months ago	64-72355 64 days ago	13-72716 13 days
34028	floor-licker author:floor-licker	feat(SimpleGraph): add max-flow/min-cut weak duality	This PR introduces a basic s–t flow setup for undirected SimpleGraphs and proves the standard weak-duality inequality: for any feasible flow f and any s–t cut S, value f ≤ cutCapacity S. This is a small, self-contained lemma I extracted while working on larger graph-theoretic formalizations, in particular, results that will ultimately rely on a full max-flow/min-cut theorem. The full MFMC equality/existence statement is not included here. This is the weak-duality direction (∀ f S, value f ≤ cutCapacity S).	t-combinatorics new-contributor	169/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Connectivity/MaxFlowMinCut.lean	2	14	['SnirBroshi', 'floor-licker', 'github-actions', 'mathlib-merge-conflicts']	kmill assignee:kmill	122-50046 4 months ago	75-50665 75 days ago	60-17070 60 days
32609	PrParadoxy author:PrParadoxy	feat(LinearAlgebra/PiTensorProduct): Relation between nested tensor products and tensor products indexed by dependent sums	Product tensors in `⨂ j : (Σ i, β i), s j.fst j.snd` can be mapped to product tensors in `⨂ i, ⨂ b : β i, s i b`. If the outer index type is finite, the two types are equivalent. This allows the definition of endomorphisms on PiTensorProducts by specifying them on disjoint subsets of the index set. Such constructions are common e.g. in quantum circuits, quantum cellular automata, and renormalization procedures. --- WIP. This PR contains two "requests for comments". Essentially: * Is a single complex-to-define linear equivalence preferable over several less complex ones, which might however be of limited interest by themselves? * Which trade-offs are appropriate to make things computable? - [ ] depends on: #32608 - [x] depends on: #32600 - [x] depends on: #32598 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor blocked-by-other-PR merge-conflict t-algebra label:t-algebra$	683/0	Mathlib.lean,Mathlib/Data/Sigma/Basic.lean,Mathlib/LinearAlgebra/Multilinear/Basic.lean,Mathlib/LinearAlgebra/PiTensorProduct/Nested.lean,Mathlib/LinearAlgebra/PiTensorProduct/Set.lean	5	5	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	121-62157 4 months ago	175-62595 175 days ago	0-614 10 minutes
30260	imbrem author:imbrem	feat(CategoryTheory/Monoidal): added CocartesianMonoidalCategory	As discussed in #21603 and #28718; this implements chosen finite coproducts on top of `AddMonoidalCategory` as defined in #30150 --- - [ ] depends on: #30150 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR large-import new-contributor t-category-theory	839/125	Mathlib.lean,Mathlib/CategoryTheory/Monoidal/Category.lean,Mathlib/CategoryTheory/Monoidal/Cocartesian/Basic.lean,Mathlib/CategoryTheory/Monoidal/Discrete.lean,Mathlib/Tactic/ToAdditive/GuessName.lean	5	4	['github-actions', 'imbrem', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	121-14588 4 months ago	unknown	unknown
30258	imbrem author:imbrem	feat(CategoryTheory/Monoidal): to_additive for proofs using `monoidal`	Building on #30150, this allows us to use `@[to_additive]` on proofs containing `monoidal`, by tagging the lemmas `monoidal` outputs with `@[to_additive]` as appropriate. Testing on my branch [`additive-monoidal-coherence`](https://github.com/imbrem/mathlib4/tree/additive-monoidal-coherence) shows that this works. It is still future work to have either the `monoidal` tactic or a new `add_monoidal` tactic work for `AddMonoidalCategory` instances directly. --- - [ ] depends on: #30150 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict blocked-by-other-PR large-import new-contributor t-category-theory	524/140	Mathlib/CategoryTheory/Monoidal/Category.lean,Mathlib/CategoryTheory/Monoidal/Discrete.lean,Mathlib/Tactic/CategoryTheory/Monoidal/Normalize.lean,Mathlib/Tactic/CategoryTheory/Monoidal/PureCoherence.lean,Mathlib/Tactic/CategoryTheory/MonoidalComp.lean,Mathlib/Tactic/ToAdditive/GuessName.lean	6	3	['github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	121-14581 4 months ago	unknown	unknown
32742	LTolDe author:LTolDe	feat(MeasureTheory/Constructions/Polish/Basic): add class SuslinSpace	add new class `SuslinSpace` for a topological space that is an analytic set in itself This will be useful to prove the Effros Theorem, see [zulip thread](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Effros.20Theorem/with/558712441). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor awaiting-zulip t-measure-probability awaiting-author	4/0	Mathlib/MeasureTheory/Constructions/Polish/Basic.lean	1	10	['ADedecker', 'LTolDe', 'dagurtomas', 'dupuisf', 'github-actions', 'jcommelin']	PatrickMassot assignee:PatrickMassot	121-14355 4 months ago	146-84887 146 days ago	11-7478 11 days
31102	JOSHCLUNE author:JOSHCLUNE	feat: require LeanHammer	Experimenting with adding LeanHammer as a mathlib dependency --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict new-contributor t-meta	61/4	Mathlib/Tactic/Common.lean,Mathlib/Tactic/Linter/DirectoryDependency.lean,MathlibTest/Hammer.lean,lake-manifest.json,lakefile.lean	5	2	['github-actions', 'mathlib4-merge-conflict-bot']	nobody	121-5063 4 months ago	unknown	unknown
33431	gululu996-ui author:gululu996-ui	feat(Combinatorics/SimpleGraph/Bipartite): characterize bipartite simple graphs by even cycles	Add the classical characterization of bipartite simple graphs: a simple graph is bipartite if and only if every cycle has even length. Previously, mathlib has the definition of `IsBipartite` for `SimpleGraph` and various lemmas about bipartite graphs, but it does not provide this equivalence in a single theorem, so users have to reprove or reassemble it from existing results. Prove the forward direction by showing a 2-coloring alternates along any walk, so every cycle must have even length. Prove the converse by showing that if an odd cycle exists then no bipartition is possible, hence if all cycles are even the graph admits a bipartition.	new-contributor t-combinatorics awaiting-author merge-conflict	186/1	Mathlib/Combinatorics/SimpleGraph/Bipartite.lean	1	6	['NickAdfor', 'github-actions', 'jcommelin', 'mathlib-merge-conflicts']	kmill assignee:kmill	121-4795 4 months ago	123-5692 123 days ago	26-992 26 days
34007	martinwintermath author:martinwintermath	feat(Algebra/Module/Submodule/Dual): dual operator for submodules	Add new file `Dual.lean` that defines the dual operator for submodules. The main definition is * `Submodule.dual`: given a bilinear pairing `p` between two modules `M₁` and `M₂` and a submodule `S` in `M₁`, `Submodule.dual p S` is the submodule in `M₂` consisting of all points `y` such that `0 = p x y` for all `x ∈ S`. For reasons of generality, `p` is actually a general sesqui-bilinear map, that is, of the form `p : M₁ →ₛₗ[I₁] M₂ →ₛₗ[I₂] M`. This implementation of the `dual` operator for submodules is written to parallel the implementation of `PointedCone.dual`. Include some additional results: * theorems that represent the dual as the kernel of a linear map * theorems for the relation between dual and the `dualAnnihilator` and `dualCoannihilator` of a submodule. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author label:t-algebra$	236/0	Mathlib.lean,Mathlib/Algebra/Module/Submodule/Dual.lean	2	7	['github-actions', 'joelriou', 'martinwintermath', 'mathlib-bors']	joelriou assignee:joelriou	121-832 4 months ago	122-69691 122 days ago	14-81283 14 days
34291	YellPika author:YellPika	feat(Data): a monad for partial computations	This is the code corresponding to [mathlib4 > A monad for partial computations](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/A.20monad.20for.20partial.20computations/with/569619800). Not currently intended to be merged. This PR depends on #33941. The only changes relevant to this discussion are in `OmegaPart.lean`, `OmegaProp.lean`, and `Quot.lean`. # Original Message Inspired by @Aaron Liu's comments in #mathlib4>deprecate Mathlib.Data.Nat.PartENat?@538009243 and #Is there code for X?>Divergence monad@538020049 I made an attempt at constructing a monad for partial computations with a computable `OmegaCompletePartialOrder` instance (neither `Option` nor `Part` support this use case). My solution consists of three parts. A computable version of `Quotient.choice`. As mentioned in #lean4>Quot.lift for dependent products@467436416 , the "obvious" computational interpretation of `Quotient.choice : (∀i:I, @Quotient (A i) …) → @Quotient (∀i:I, A i)` is not sound. However, we _can_ provide a sound computational interpretation when we restrict `I` to `ℕ`: ```lean unsafe def Quotient.countableChoice_impl {α : Nat → Type} {S : ∀ i, Setoid (α i)} (f : ∀ i, Quotient (S i)) : @Quotient (∀ i, α i) (by infer_instance) := Quotient.lift₂ (fun z s ↦ ⟦fun \| .zero => z \| .succ n => s n⟧) (fun z₁ s₁ z₂ s₂ h₁ h₂ ↦ by apply sound rintro ⟨_\|n⟩ · apply h₁ · apply h₂) (f 0) (countableChoice_impl (fun n ↦ f n.succ)) @[implemented_by Quotient.countableChoice_impl] def Quotient.countableChoice {α : Nat → Type} {S : ∀ i, Setoid (α i)} (f : ∀ i, Quotient (S i)) : @Quotient (∀ i, α i) (by infer_instance) := Quotient.choice f ``` My justification for the soundness of this implementation comes from the fact that only uses existing (sound and computable) functions + general recursion. The implementation is found [here](https://github.com/YellPika/mathlib4/blob/99d38f164a97c7aa225283ef6016f0279419a994/Mathlib/Data/Quot.lean#L430) (it uses `unquot` instead of recursion for performance reasons, but should be equivalent). A type of semi-computable propositions. Next, I define a type of semi-computable propositions `ΩProp` as a quotient of the type of boolean sequences `(ℕ → Bool) / ≈`, where `p ≈ q ≝ (∃n, p n) ↔ (∃n, q n)`. A sequence is interpreted as "true" if at least one element in the sequence is `true`, and the quotient relation ensures that we cannot observe the difference between different "true" sequences. The `ΩProp` type has a (computable) `OmegaCompletePartialOrder`, and `Quotient.countableChoice` is used in the implementation of `ωSup`. The implementation of this type is [here](https://github.com/YellPika/mathlib4/blob/quot-choice-compute/Mathlib/Data/OmegaProp.lean). A type of semi-computable computations. Finally, I define the type `ΩPart A` of semi-computable computations returning a value of type `A`. The definition of `ΩPart` is the same as `Part` with `ΩProp` swapped for `Prop`. Again, `ΩPart A` has a (computable) `OmegaCompletePartialOrder` instance. The implementation can be found [here](https://github.com/YellPika/mathlib4/blob/quot-choice-compute/Mathlib/Data/OmegaPart.lean). This was mainly just a fun experiment and the code is not ready to be (or perhaps should not be) put in mathlib. I thought I should post it here to see if 1) there is any interest or 2) an implementation already exists that has escaped my notice.	new-contributor large-import merge-conflict	1157/40	Mathlib/Data/OmegaPart.lean,Mathlib/Data/OmegaProp.lean,Mathlib/Data/Quot.lean,Mathlib/Order/OmegaCompletePartialOrder.lean,Mathlib/Order/ScottContinuity.lean	5	2	['github-actions', 'mathlib-merge-conflicts']	nobody	118-69716 3 months ago	unknown	unknown
34053	christian-oudard author:christian-oudard	feat: Add error function (erf) and complementary error function (erfc)	## Summary I was doing some finance math and needed the Error Function, so I thought I'd contribute it. ### Main definitions * `Real.erf`: The error function, defined as `(2/√π) ∫₀ˣ e^(-t²) dt` * `Real.erfc`: The complementary error function, defined as `1 - erf x` ### Main results * `Real.erf_zero`: `erf 0 = 0` * `Real.erf_neg`: `erf` is an odd function: `erf (-x) = -erf x` * `Real.erf_tendsto_one`: `erf x → 1` as `x → ∞` * `Real.erf_tendsto_neg_one`: `erf x → -1` as `x → -∞` * `Real.erf_le_one`: `erf x ≤ 1` for all `x` * `Real.neg_one_le_erf`: `-1 ≤ erf x` for all `x` * `Real.deriv_erf`: `deriv erf x = (2/√π) * exp(-x²)` * `Real.differentiable_erf`: `erf` is differentiable * `Real.continuous_erf`: `erf` is continuous * `Real.strictMono_erf`: `erf` is strictly monotone Also adds `erf` to `docs/overview.yaml` under Special Functions. --- - [x] Builds successfully - [x] `lake exe runLinter` passes - [x] `lake exe mk_all --check` passes	t-analysis new-contributor awaiting-author	333/0	Mathlib.lean,Mathlib/Analysis/SpecialFunctions/Erf.lean,docs/overview.yaml	3	18	['SnirBroshi', 'christian-oudard', 'github-actions', 'j-loreaux', 'plp127']	j-loreaux assignee:j-loreaux	118-42492 3 months ago	118-79345 118 days ago	14-65488 14 days
33601	nielstron author:nielstron	feat(Computability/ContextFreeGrammar): Concatenation of CFGs is CFG	--- - [ ] depends on: #33599 - [ ] depends on: #33592 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-computability new-contributor blocked-by-other-PR	941/0	Mathlib/Computability/ContextFreeGrammar.lean	1	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	118-20205 3 months ago	148-4068 148 days ago	0-315 5 minutes
34726	GrigorenkoPV author:GrigorenkoPV	feat(Analysis/SpecialFunctions/Trigonometric/Basic): sin and cos of multiples of π / 3	--- Merge of https://github.com/leanprover-community/mathlib4/pull/26349 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor	159/0	Mathlib/Algebra/Order/Monoid/NatCast.lean,Mathlib/Analysis/SpecialFunctions/Trigonometric/Basic.lean,Mathlib/Data/Nat/Cast/Defs.lean,MathlibTest/trigonometry.lean	4	1	['github-actions']	nobody	116-65630 3 months ago	unknown	unknown
34394	Citronhat author:Citronhat	feat(Algebra/Order/Ring): add constructors for linear ordered rings	Add constructors for ordered rings from `mul_nonneg` / `mul_pos` that derive `ZeroLEOneClass` from a linear order.	new-contributor t-algebra awaiting-author label:t-algebra$	31/14	Mathlib/Algebra/Order/Ring/Defs.lean,Mathlib/RingTheory/HahnSeries/Lex.lean	2	6	['Citronhat', 'Vierkantor', 'github-actions', 'leanprover-radar']	Vierkantor assignee:Vierkantor	116-12567 3 months ago	116-12567 116 days ago	12-16957 12 days
33493	michelsol author:michelsol	feat(RingTheory/Polynomial): An explicit formula for the Chebyshev polynomials of the first kind	Adds the following explicit formula on the Chebyshev polynomial of the first kind of order n. ${ T_{n}(x)\ =\ \sum \limits _{k=0}^{\lfloor {\frac {n}{2}}\rfloor } {\binom {n}{2k}} \left(\ X^{2}-1\ \right)^{k}\ X^{n-2k}}$ This explicit formula can be found [here](https://en.wikipedia.org/wiki/Chebyshev_polynomials#Explicit_expressions). There is a proof using complex numbers but it only works if the ring R = ℂ. The proof here is by induction and works in a commutative ring R. Mathlib seems to extend the definition of Chebyshev polynomials for $n \in \mathbb{Z}$ but this would make the formula more cumbersome with `n.natAbs` in place of `n`'s, so I expressed it on `n : ℕ` directly. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory new-contributor awaiting-author	51/1	Mathlib/RingTheory/Polynomial/Chebyshev.lean	1	8	['YuvalFilmus', 'erdOne', 'github-actions', 'metakunt', 'michelsol']	chrisflav assignee:chrisflav	114-48806 3 months ago	114-48806 114 days ago	35-14906 35 days
34815	Deep0Thinking author:Deep0Thinking	feat(Analysis/SpecialFunctions/ImproperIntegrals): Frullani integral	- [x] depends on: #34966 --- Add a proof of Frullani integral. Main theorems: - `Frullani.integral_Ioi` - `IntegrableOn.tendsto_integral_Ioi` - `exists_integral_div_eq_mul_log` Supporting lemmas: - `Frullani.comp_mul_left_div` - `Frullani.intervalIntegrable_div` - `Frullani.exists_integral_div_eq_mul_log` - `Ioi_diff_Ioc` - `ContinuousOn.comp_mul_left_div`, `ContinuousOn.comp_mul_right_div` - `ContinuousOn.comp_mul_left`, `ContinuousOn.comp_mul_right` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor large-import t-analysis awaiting-author blocked-by-other-PR	270/2	Mathlib/Analysis/SpecialFunctions/ImproperIntegrals.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/MeanValue.lean,Mathlib/Topology/Algebra/GroupWithZero.lean,Mathlib/Topology/Algebra/Monoid.lean	6	17	['CoolRmal', 'Deep0Thinking', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'sgouezel']	urkud assignee:urkud	114-32521 3 months ago	37-68971 37 days ago	11-30747 11 days
26986	WangYiran01 author:WangYiran01	feat(Partition): add bijection for partitions with max part ≤ r	This PR adds a new theorem `partition_max_equals_bound` to `Mathlib.Combinatorics.Enumerative.Partition`. It constructs a bijection between: - The set of partitions of `n` in which `r ∈ π.parts` and all parts are `≤ r`, and - The set of partitions of `n - r` whose largest part is at most `r`. This provides a constructive proof via removing/adding `r` from/to the partition multiset, in line with classical enumerative combinatorics. Contributed by Yiran Wang.	awaiting-author t-combinatorics new-contributor merge-conflict	92/0	Mathlib/Combinatorics/Enumerative/Partition/Basic.lean,Mathlib/Data/Multiset/Lattice.lean	2	20	['WangYiran01', 'github-actions', 'jcommelin', 'kckennylau', 'kim-em', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot']	b-mehta assignee:b-mehta	111-83680 3 months ago	145-20148 145 days ago	18-14180 18 days
26168	oliver-butterley author:oliver-butterley	feat(MeasureTheory.VectorMeasure): variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition	Add `signedMeasure_totalVariation_eq`: if `μ` is a `SignedMeasure` then variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition. Co-authored-by: @yoh-tanimoto --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-measure-probability awaiting-author merge-conflict blocked-by-other-PR new-contributor	916/0	Mathlib.lean,Mathlib/MeasureTheory/VectorMeasure/Decomposition/Jordan.lean,Mathlib/MeasureTheory/VectorMeasure/Variation/Equiv.lean	5	7	['github-actions', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot', 'yoh-tanimoto']	nobody	111-64669 3 months ago	unknown	unknown
34722	GrigorenkoPV author:GrigorenkoPV	feat(Data/Finset/RangeDistance): bound distance between elements of `Finset.range`	--- Rebase of https://github.com/leanprover-community/mathlib4/pull/26347 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-data awaiting-author	34/0	Mathlib.lean,Mathlib/Algebra/Order/Group/Unbundled/Abs.lean,Mathlib/Data/Finset/RangeDistance.lean	3	7	['GrigorenkoPV', 'Vierkantor', 'github-actions', 'joneugster', 'mathlib-splicebot', 'plp127']	pechersky assignee:pechersky	111-49958 3 months ago	67-73720 67 days ago	52-17049 52 days
33969	goliath-klein author:goliath-klein	refactor(PiTensorProduct/{InjectiveNorm, ProjectiveNorm}): Currently, injectiveSeminorm = projectiveSeminorm	WIP / RFC! Arguably, `injectiveSeminorm` should be re-defined in Mathlib. See #34137 and [Zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/injectiveSeminorm/with/568798261) for context. In this file, we collect some results about the current definition and a possible alternative. Contents: * A theorem `injectiveSeminorm_eq_projectiveSeminorm` formalizing the equality of the current definitions. However, I think it is unlikely that keeping the alternative characterization would be worth the effort. The interesting direction `(L2') ≤ (L1)` follows from `norm_eval_le_projectiveSeminorm` which is still present. The converse direction is [somewhat tautological](https://github.com/leanprover-community/mathlib4/pull/34137). A proof of `(L2) = (L1)` (probably requiring Hahn-Banach) might be more interesting. * A preliminary implementation of the injective seminorm as commonly understood. * Sufficient conditions for the multiplicativity property `‖⨂ m i‖_∧ = ∏ ‖m i‖` to hold. This implements a TBD item. --- Co-authored-by: Davood H. H. Tehrani [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-analysis new-contributor large-import merge-conflict	774/387	Mathlib.lean,Mathlib/Analysis/Normed/Module/Dual.lean,Mathlib/Analysis/Normed/Module/HahnBanach.lean,Mathlib/Analysis/Normed/Module/PiTensorProduct/InjectiveSeminorm.lean,Mathlib/Analysis/Normed/Module/PiTensorProduct/LeastReasonable.lean,Mathlib/Analysis/Normed/Module/PiTensorProduct/ProjectiveSeminorm.lean,Mathlib/Analysis/Normed/Operator/Basic.lean,Mathlib/LinearAlgebra/PiTensorProduct.lean	8	3	['github-actions', 'goliath-klein', 'mathlib-merge-conflicts']	nobody	110-67030 3 months ago	unknown	unknown
33233	jazzits author:jazzits	feat(GroupTheory): add chosen group presentations and Tietze transformations (1) and (2)	Defines a notion of group presentation for G compatible with Mathlib.GroupTheory.PresentedGroup: generators `ι → G` whose range generates G, and relators `rels : Set (FreeGroup ι)` whose normal closure equals the kernel of `FreeGroup ι →* G`. Provides the canonical map `PresentedGroup P.rels →* G` and equivalences showing `PresentedGroup P.rels ≃* G` and invariance under changing presentations. Also formalizes Tietze moves (1)–(2) as equivalences of PresentedGroups: adding/removing a relator that lies in the normal closure of the others. TODO: moves (3)–(4) (add/remove generator with a defining relation). No existing definitions are modified	t-group-theory new-contributor awaiting-author	328/0	Mathlib.lean,Mathlib/GroupTheory/Presentation.lean	2	15	['github-actions', 'homeowmorphism', 'jazzits', 'kbuzzard', 'mathlib-merge-conflicts', 'plp127', 'tb65536']	tb65536 assignee:tb65536	110-9163 3 months ago	155-1710 155 days ago	5-46468 5 days
34725	GrigorenkoPV author:GrigorenkoPV	feat(RingTheory/RootsOfUnity/LowDegree): quadratic, cubic, quartic, quintic roots of unity	Closes https://github.com/leanprover-community/mathlib4/pull/25907 --- Merge of https://github.com/leanprover-community/mathlib4/pull/25907 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-ring-theory awaiting-author	247/0	Mathlib.lean,Mathlib/Algebra/CharP/Invertible.lean,Mathlib/Algebra/QuadraticDiscriminant.lean,Mathlib/RingTheory/RootsOfUnity/LowDegree.lean	4	22	['GrigorenkoPV', 'LLaurance', 'erdOne', 'github-actions', 'joneugster']	nobody	109-60253 3 months ago	114-49573 114 days ago	4-36005 4 days
33032	ksenono author:ksenono	feat(Combinatorics/SimpleGraph): Konig’s theorem on bipartite graphs	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor blocked-by-other-PR merge-conflict	832/251	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Bipartite.lean,Mathlib/Combinatorics/SimpleGraph/Clique.lean,Mathlib/Combinatorics/SimpleGraph/DegreeSum.lean,Mathlib/Combinatorics/SimpleGraph/Konig/Auxillary.lean,Mathlib/Combinatorics/SimpleGraph/Konig/Konig.lean,Mathlib/Combinatorics/SimpleGraph/Konig/KonigFin.lean,Mathlib/Combinatorics/SimpleGraph/Matching.lean,Mathlib/Combinatorics/SimpleGraph/Subgraph.lean,Mathlib/Combinatorics/SimpleGraph/VertexCover.lean,Mathlib/SetTheory/Cardinal/Arithmetic.lean,Mathlib/SetTheory/Cardinal/Basic.lean	12	9	['SnirBroshi', 'github-actions', 'ksenono', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'vlad902']	nobody	109-44163 3 months ago	unknown	unknown
34159	wangying11123 author:wangying11123	feat(Geometry/Euclidean/Similarity): Add Triangle similarity on oangle	Add theorems about triangles similarity on oangle	t-euclidean-geometry new-contributor awaiting-author	154/1	Mathlib/Geometry/Euclidean/Similarity.lean	1	8	['LLaurance', 'github-actions', 'jsm28', 'wangying11123']	jsm28 assignee:jsm28	109-7930 3 months ago	109-55159 109 days ago	1-73119 1 day
33050	mkaratarakis author:mkaratarakis	feat: lemmas for the analytic part of the proof of the Gelfond–Schneider theorem	Lemmas missing for the formalisation of the proof of the Gelfond–Schneider theorem --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor WIP	238/0	Mathlib.lean,Mathlib/Analysis/Analytic/Basic.lean,Mathlib/Analysis/Analytic/Order.lean,Mathlib/Analysis/Complex/CauchyIntegral.lean,Mathlib/NumberTheory/Transcendental/AnalyticPart.lean,Mathlib/NumberTheory/Transcendental/AnalyticPart2.lean	6	113	['SnirBroshi', 'github-actions', 'j-loreaux', 'mkaratarakis', 'riccardobrasca', 'vihdzp']	riccardobrasca assignee:riccardobrasca	107-76710 3 months ago	118-9567 118 days ago	6-26143 6 days
34814	GrigorenkoPV author:GrigorenkoPV	feat(Tactic/ClearUnneeded): add `clear_unneeded` tactic	--- The simplest version suggested in https://github.com/leanprover-community/mathlib4/issues/25319 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta new-contributor please-merge-master awaiting-author	94/0	Mathlib.lean,Mathlib/Tactic.lean,Mathlib/Tactic/ClearUnneeded.lean,Mathlib/Tactic/Common.lean,MathlibTest/ClearUnneeded.lean,scripts/noshake.json	6	12	['BoltonBailey', 'GrigorenkoPV', 'github-actions', 'joneugster']	joneugster assignee:joneugster	107-63774 3 months ago	116-747 116 days ago	2-13297 2 days
34876	GrigorenkoPV author:GrigorenkoPV	feat(Tactic/AssumptionQuestion): add `assumption?` tactic	--- As requested in #10361 TODO: maybe add some tests? [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta new-contributor awaiting-author	85/0	Mathlib.lean,Mathlib/Tactic.lean,Mathlib/Tactic/AssumptionQuestion.lean,Mathlib/Tactic/Common.lean,MathlibTest/AssumptionQuestion.lean,scripts/noshake.json	6	5	['GrigorenkoPV', 'SnirBroshi', 'github-actions', 'joneugster']	joneugster assignee:joneugster	107-62349 3 months ago	115-85337 115 days ago	0-79222 22 hours
33217	Blackfeather007 author:Blackfeather007	feat(Algebra): define associated graded structure for abelian group	In this PR we define the associated graded structure for abelian group when given a filtration and only give some basic lemmas about it. --- migrated from https://github.com/leanprover-community/mathlib4/pull/26857	new-contributor t-ring-theory awaiting-author	144/0	Mathlib.lean,Mathlib/RingTheory/FilteredAlgebra/AssociatedGraded.lean	2	13	['Blackfeather007', 'chrisflav', 'erdOne', 'eric-wieser', 'github-actions', 'urkud']	erdOne assignee:erdOne	107-49930 3 months ago	156-64326 156 days ago	4-56728 4 days
23791	SEU-Prime author:SEU-Prime	Create AmiceTrans.lean	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict WIP t-number-theory new-contributor	2963/0	Mathlib.lean,Mathlib/Analysis/Normed/Ring/Lemmas2.lean,Mathlib/NumberTheory/Padics/AmiceTrans.lean,Mathlib/NumberTheory/Padics/PSAC.lean,Mathlib/NumberTheory/Padics/PSAC2.lean,Mathlib/NumberTheory/Padics/PSAC3.lean,Mathlib/NumberTheory/Padics/PiGammainPS.lean,Mathlib/NumberTheory/Padics/PsiandVar.lean,Mathlib/RingTheory/AdicCompletion/Lemma.lean,Mathlib/RingTheory/PowerSeries/Comp.lean,Mathlib/Topology/ContinuousMap/ZeroAtBot.lean	11	5	['SEU-Prime', 'github-actions', 'leanprover-community-bot-assistant', 'urkud']	nobody	107-48994 3 months ago	unknown	unknown
33281	michelsol author:michelsol	feat(Analysis/SpecialFunctions/Integrals): integral of 1/sqrt(1-x^2) and its integrability.	Add the integral of the derivative of arcsin and its integrability. --- - [ ] depends on: #33280 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict t-analysis	59/0	Mathlib/Analysis/SpecialFunctions/Integrability/Basic.lean,Mathlib/Analysis/SpecialFunctions/Integrals/Basic.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/FundThmCalculus.lean	3	3	['github-actions', 'mathlib-dependent-issues', 'mathlib4-merge-conflict-bot']	nobody	107-18617 3 months ago	unknown	unknown
32918	michelsol author:michelsol	feat: define `supEdist` and `supDist`	Create a new file Topology.MetricSpace.SupDistance and define the supremal distance in (extended) metric spaces. The defined `supEdist` and `supDist` will have similar theory to the already existing `infEdist` and `infDist`. The motivation is to be able to define the radius of a minimal bounding sphere as the infimum of the supDist later. [zulip discussion here](https://leanprover.zulipchat.com/#narrow/channel/116395-maths/topic/Formalizing.20Jung's.20theorem.20and.20minimal.20bounding.20spheres)	t-topology new-contributor merge-conflict	75/0	Mathlib.lean,Mathlib/Topology/MetricSpace/SupDistance.lean	2	5	['github-actions', 'mathlib4-merge-conflict-bot', 'michelsol', 'urkud']	nobody	105-75116 3 months ago	147-67501 147 days ago	21-1998 21 days
33712	wangying11123 author:wangying11123	feat(Geometry/Euclidean/Angle/Unoriented/Projection): Add sameray_orthogonalProjection_vsub_of_angle_lt	Add sameray_orthogonalProjection_vsub_of_angle_lt `sameray_orthogonalProjection_vsub_of_angle_lt` When an angle is acute, the vector to the orthogonal projection lies in the same ray as the given direction vector.	new-contributor t-euclidean-geometry awaiting-author	20/0	Mathlib/Geometry/Euclidean/Angle/Unoriented/Projection.lean	1	4	['JovanGerb', 'github-actions', 'j-loreaux']	JovanGerb assignee:JovanGerb	104-84947 3 months ago	104-85047 104 days ago	34-1568 34 days
30667	FrederickPu author:FrederickPu	feat(‎Mathlib/Algebra/Group/Subgroup/Pointwise): subgroup mul	Title: feat: pointwise products for subgroups Description: showed the point-wise product of disjoint subgroups is equivalent to their Cartesian product. Based on https://leanprover.zulipchat.com/#narrow/channel/113488-general/topic/useful.20group.20theory.20lemmas/with/546738566. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor label:t-algebra$	28/0	Mathlib/Algebra/Group/Subgroup/Pointwise.lean	1	23	['FrederickPu', 'eric-wieser', 'github-actions', 'plp127', 'tb65536']	nobody	104-83456 3 months ago	105-1690 105 days ago	1-16352 1 day
33793	LTolDe author:LTolDe	feat(MeasureTheory/Constructions/Polish/Basic): add lemma AnalyticSet.inter_nonempty_of_nowhereMeagre	add lemma AnalyticSet.inter_nonempty_of_nowhereMeagre, the main ingredient for the proof of the Effros' Theorem, see [#mathlib4 > Effros Theorem](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Effros.20Theorem/with/566543328) introduce definition of a nowhere meagre set --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-measure-probability new-contributor awaiting-author	37/0	Mathlib/MeasureTheory/Constructions/Polish/Basic.lean,Mathlib/Order/Filter/Basic.lean,Mathlib/Topology/GDelta/Basic.lean	3	8	['MichaelStollBayreuth', 'erdOne', 'github-actions', 'j-loreaux']	kex-y assignee:kex-y	104-79213 3 months ago	104-79419 104 days ago	39-9506 39 days
35313	LexinonCraft author:LexinonCraft	feat: IMO 2025 Q4	This adds a solution for problem 4 from the International Math Olympiad 2025. ---	IMO new-contributor awaiting-author	631/0	Archive.lean,Archive/Imo/Imo2025Q4.lean	2	4	['LexinonCraft', 'github-actions', 'jsm28']	jsm28 assignee:jsm28	104-49087 3 months ago	unknown	unknown
33276	NicolaBernini author:NicolaBernini	feat: Rename List.reverse_perm to List.reverse_perm_self and List.reverse_perm' to List.reverse_perm_iff	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor awaiting-author t-data merge-conflict	17/15	Mathlib/Algebra/BigOperators/Group/List/Basic.lean,Mathlib/Data/Finset/Dedup.lean,Mathlib/Data/List/Basic.lean,Mathlib/Data/List/Defs.lean,Mathlib/Data/List/Perm/Lattice.lean,Mathlib/Data/List/Permutation.lean,Mathlib/Data/Multiset/Defs.lean,Mathlib/NumberTheory/Divisors.lean	8	5	['Ruben-VandeVelde', 'github-actions', 'mathlib-merge-conflicts']	kim-em assignee:kim-em	104-32831 3 months ago	155-11104 155 days ago	2-58880 2 days
34674	Citronhat author:Citronhat	feat(Algebra/Order/Ring): replace ENNReal lemmas with WithTop versions	* Add `WithTop` versions of basic multiplicative order lemmas. * Use the new `WithTop` lemmas to replace `ENNReal` proofs and address six TODOs. * Fix a typo in the `pos_of_ne_zero` alias name.	new-contributor t-algebra merge-conflict label:t-algebra$	46/15	Mathlib/Algebra/Order/Monoid/Canonical/Defs.lean,Mathlib/Algebra/Order/Ring/WithTop.lean,Mathlib/Data/ENNReal/Operations.lean	3	5	['Citronhat', 'Ruben-VandeVelde', 'github-actions', 'mathlib-merge-conflicts']	Ruben-VandeVelde assignee:Ruben-VandeVelde	104-12565 3 months ago	104-12566 104 days ago	15-44183 15 days
28246	Sebi-Kumar author:Sebi-Kumar	feat(AlgebraicTopology/FundamentalGroupoid): the n-sphere is simply connected for n > 1	Prove that the `n`-dimensional sphere (i.e., the unit sphere centered at the origin in `(n + 1)`-dimensional real Euclidean space) is a simply connected space for `n > 1`. This proof follows Hatcher's "Algebraic Topology"; we first prove a general lemma about decomposing loops and then exploit the fact that non-surjective loops in the sphere are homotopically trivial. Note: To get this file to build, I edited `Mathlib/Tactic/Linter/DirectoryDependency.lean` to remove the restrictions on AlgebraicTopology files importing Geometry, NumberTheory, and FieldTheory files. Thank you to those who shared their expertise [here](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Warning.20that.20AlgebraicTopology.20can't.20import.20SetTheory/with/533833638). As I understand it, this is just a short-term solution, so I would appreciate feedback on what to do about this situation. Note: I am unsure where exactly the file `SimplyConnectedSphere.lean` should go or whether that is an appropriate name for the file, so feedback there would be appreciated. --- To provide additional context, this code was written as a part of the Fields Undergraduate Summer Research Program at the University of Western Ontario under the supervision of Chris Kapulkin and Daniel Carranza. - [x] depends on: #28208 - [x] depends on: #28198 - [x] depends on: #28185 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebraic-topology new-contributor awaiting-author	343/3	Mathlib.lean,Mathlib/AlgebraicTopology/FundamentalGroupoid/SimplyConnectedSphere.lean,Mathlib/Tactic/Linter/DirectoryDependency.lean	3	17	['dagurtomas', 'github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'robin-carlier']	robin-carlier assignee:robin-carlier	102-10351 3 months ago	102-10351 102 days ago	13-72176 13 days
33746	ster-oc author:ster-oc	feat(Algebra/Module/ZLattice): align `ZSpan.floor` to `Int.floor` API	This PR adds some of the existent lemmas about `Int.floor`, `Int.ceil` and `Int.fract` to the `ZSpan` namespace. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor merge-conflict label:t-algebra$	353/145	Mathlib/Algebra/Module/ZLattice/Basic.lean,Mathlib/Algebra/Order/Floor/Ring.lean,Mathlib/Topology/Algebra/Order/Floor.lean	3	8	['github-actions', 'joelriou', 'mathlib-merge-conflicts', 'ster-oc']	joelriou assignee:joelriou	99-29463 3 months ago	99-29463 99 days ago	6-29290 6 days
31766	SuccessMoses author:SuccessMoses	feat(Topology/EMetricSpace): continuity of arc length	fixes half of #31751 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-topology awaiting-author merge-conflict	396/0	Mathlib.lean,Mathlib/Topology/EMetricSpace/ArcLength.lean,Mathlib/Topology/EMetricSpace/BoundedVariation.lean	3	40	['SnirBroshi', 'SuccessMoses', 'alreadydone', 'github-actions', 'grunweg', 'j-loreaux', 'mathlib-merge-conflicts']	nobody	98-61160 3 months ago	174-62030 174 days ago	2-76934 2 days
34419	ster-oc author:ster-oc	feat(RCLike): add `Continuous.re` and similar	This PR adds dot notation for `re`, `im`, `conj` and `ofReal` for `Continuous`, `LipschitzWith` and `Memℓp`. Given `hf : Continuous f` it allows to use `hf.re` to express `Continuous (fun x ↦ (f x).re)`, similarly to the usual `hf.add hg`. I also can add the same features for `Summable` but I am not sure where to place them, suggestions are appreciated! --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis new-contributor awaiting-author merge-conflict	186/41	Mathlib/Analysis/Normed/Group/Uniform.lean,Mathlib/Analysis/Normed/Lp/lpSpace.lean,Mathlib/Analysis/RCLike/Basic.lean	3	15	['github-actions', 'j-loreaux', 'mathlib-merge-conflicts', 'ster-oc']	j-loreaux assignee:j-loreaux	97-73258 3 months ago	97-73258 97 days ago	8-26131 8 days
33247	sun123zxy author:sun123zxy	feat(Mathlib/RingTheory/Ideal/Cotangent): dimension of cotangent spaces	It is shown that the span rank of the maximal ideal of a local ring equals the dimension of the cotangent space if the maximal ideal is finitely generated. To avoid unnecessary imports, the original `Mathlib/RingTheory/Nakayama` is now moved to `Mathlib/RingTheory/Nakayama/Basic`. --- - [ ] depends on: #33359 - [ ] depends on: #33361 - [ ] depends on: #35651 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	file-removed new-contributor t-ring-theory WIP blocked-by-other-PR merge-conflict	140/27	Mathlib.lean,Mathlib/RingTheory/Ideal/Cotangent.lean,Mathlib/RingTheory/Ideal/KrullsHeightTheorem.lean,Mathlib/RingTheory/Ideal/Quotient/Operations.lean,Mathlib/RingTheory/LocalRing/Module.lean,Mathlib/RingTheory/LocalRing/Quotient.lean,Mathlib/RingTheory/Nakayama/Basic.lean,Mathlib/RingTheory/Nakayama/SpanRank.lean,Mathlib/RingTheory/Regular/RegularSequence.lean,Mathlib/RingTheory/Support.lean	10	13	['erdOne', 'github-actions', 'mathlib-bors', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'sun123zxy']	nobody	97-57496 3 months ago	156-64644 156 days ago	3-72713 3 days
34853	GrigorenkoPV author:GrigorenkoPV	feat(Combinatorics/Enumerative/Catalan): ratio of subsequent Catalan numbers	--- Should I split this into 2 PRs? Otherwise it'll get squashed & be less concise. UPD: ok, I've opened #34854 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict	305/195	Mathlib.lean,Mathlib/Combinatorics/Enumerative/Catalan.lean,Mathlib/Combinatorics/Enumerative/Catalan/Basic.lean,Mathlib/Combinatorics/Enumerative/Catalan/Ratio.lean,Mathlib/Combinatorics/Enumerative/Catalan/Tree.lean,Mathlib/Combinatorics/Enumerative/DyckWord.lean,Mathlib/RingTheory/PowerSeries/Catalan.lean	7	6	['github-actions', 'mathlib-merge-conflicts', 'vihdzp']	nobody	97-57119 3 months ago	115-84804 115 days ago	1-61543 1 day
35735	mkaratarakis author:mkaratarakis	feat(NumberTheory): analytical properties and lower bounds for Gelfond-Schneider auxiliary function	This PR is the third component in the formalization of the Gelfond-Schneider Theorem (Hilbert's Seventh Problem). It connects the algebraically constructed auxiliary function `R(x)` to its analytical properties, establishing the exact order of vanishing and the fundamental lower bound on the norm of its non-zero derivative evaluation. Following the argument in Loo-Keng Hua's Introduction to Number Theory (Chapter 17.9, equations (4) and (5)), we define the minimal non-vanishing derivative order $r$ and scale the evaluation to an algebraic integer to compute its norm. 1. (`iteratedkDeriv_R_eq_zero` & `order_geq_n`): We verify that the coefficient vector $\eta$ (chosen via Siegel's lemma in the previous PR) forces the first $n$ derivatives of the auxiliary function $R(x)$ to vanish at the points $x \in \{1, 2, \dots, m\}$. Consequently, the analytical order of $R(x)$ at these points is at least $n$. 2. We extract $r$, the exact minimal order of vanishing of $R(x)$ among all points $1 \le l \le m$, and prove that $n \le r$. 3. We define the non-zero algebraic number $\rho = (\log \alpha)^{-r} R^{(r)}(l_0)$. 4. We prove the crucial textbook step that scaling $\rho$ by $c_1^{r+2mq}$ (formalized here as `cρ`) results in an algebraic integer in $\mathcal{O}_K$. 5. Because $c_1^{r+2mq} \rho$ is a non-zero algebraic integer, the absolute value of its norm is at least $1$. We use this to formally prove the strict lower bound on the absolute norm of the unscaled $\rho$: $\|N(\rho)\| > c_1^{-h(r+2mq)} > c_5^{-r}$. --- - [ ] depends on: #35734 [optional extra text] [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor blocked-by-other-PR	1141/0	Mathlib.lean,Mathlib/NumberTheory/Transcendental/GelfondSchneider/MainAlg.lean,Mathlib/NumberTheory/Transcendental/GelfondSchneider/MainAlgSetup.lean,Mathlib/NumberTheory/Transcendental/GelfondSchneider/MainOrder.lean	4	3	['github-actions', 'mathlib-dependent-issues']	nobody	97-44577 3 months ago	unknown	unknown
35755	Vilin97 author:Vilin97	feat(Analysis/ODE): forward Euler method convergence	WIP Prove the convergence of the Forward Euler Method. This is the first theorem in most textbooks on numerical analysis for ODEs. --- The initial proof was produced by [Aristotle](https://aristotle.harmonic.fun). The code was then iteratively refined (factoring out lemmas, golfing, simplifying proofs) using Claude Code (Claude Opus 4.6). * [ ] depends on: #35753	new-contributor WIP LLM-generated merge-conflict	297/0	Mathlib.lean,Mathlib/Analysis/ODE/EulerMethod.lean,Mathlib/Topology/Algebra/Order/PiecewiseLinear.lean	4	7	['Vilin97', 'eric-wieser', 'github-actions', 'mathlib-merge-conflicts']	nobody	97-21566 3 months ago	unknown	unknown
20238	maemre author:maemre	feat(Computability/DFA): Closure of regular languages under some set operations	This shows that regular languages are closed under complement and intersection by constructing DFAs for them. --- Closure under all other operations will be proved when someone adds the proof for DFA<->regular expression equivalence, so they are not part of this PR. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-computability merge-conflict awaiting-author awaiting-zulip	159/0	Mathlib/Computability/DFA.lean,Mathlib/Computability/Language.lean	2	60	['EtienneC30', 'YaelDillies', 'github-actions', 'maemre', 'mathlib4-merge-conflict-bot', 'meithecatte', 'urkud']	nobody	96-19501 3 months ago	unknown	unknown
22361	rudynicolop author:rudynicolop	feat(Computability/NFA): nfa closure properties	Add the closure properties union, intersection and reversal for NFA. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-computability merge-conflict awaiting-author awaiting-zulip	218/2	Mathlib/Computability/Language.lean,Mathlib/Computability/NFA.lean	2	91	['EtienneC30', 'b-mehta', 'ctchou', 'github-actions', 'leanprover-community-bot-assistant', 'meithecatte', 'rudynicolop']	nobody	96-19485 3 months ago	unknown	unknown
30872	rudynicolop author:rudynicolop	feat(Computability/NFA): NFA closure under concatenation	This PR proves that regular languages are closed under concatenation via a direct construction on `NFA`s without `εNFA` nor ε-transitions. The main new definitions and results include: - `M1.concat M2`, the concatenation of `NFA`s `M1` and `M2`, a direct construction without ε-transitions. - Theorem `accepts_concat : (M1.concat M2).accepts = M1.accepts * M2.accepts`, showing the correctness of the construction. - Theorem `IsRegular.mul`, showing that regular languages are closed under concatenation. --- - [x] depends on: #31038 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-computability new-contributor awaiting-author	104/7	Mathlib/Computability/NFA.lean	1	67	['YaelDillies', 'ctchou', 'eric-wieser', 'github-actions', 'lambda-fairy', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'rudynicolop']	nobody	95-85756 3 months ago	123-69165 123 days ago	59-49979 59 days
35746	ThomasMoulin-hub author:ThomasMoulin-hub	feat (Algebra/Endomorphisms): add kernels lemma from the missing undergraduate mathematics in mathlib	Add helper theorem inside Mathlib.Algebra.Polynomial.Smeval.lean and created a new file Mathlib/RingTheory/Polynomial/KernelDecomposition.lean that implements the kernels lemma from the missing undergraduate mathematics in mathlib list. This file also contains intermediate results needed for the main lemma.	new-contributor	75/0	Mathlib/Algebra/Polynomial/Smeval.lean,Mathlib/RingTheory/Polynomial/Basic.lean	2	2	['github-actions']	nobody	95-57325 3 months ago	unknown	unknown
23929	meithecatte author:meithecatte	feat(Computability/NFA): improve bound on pumping lemma	--- - [x] depends on: #25321 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-computability awaiting-zulip new-contributor awaiting-author	101/10	Mathlib/Computability/EpsilonNFA.lean,Mathlib/Computability/NFA.lean	2	42	['YaelDillies', 'dagurtomas', 'github-actions', 'leanprover-community-bot-assistant', 'mathlib4-dependent-issues-bot', 'meithecatte']	nobody	95-39514 3 months ago	359-68813 359 days ago	0-37135 10 hours
35128	DAE123456 author:DAE123456	feat : Define anti_pascal	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author label:t-algebra$	81/0	Archive.lean,Archive/Imo/Imo2018Q3.lean	2	5	['DAE123456', 'github-actions', 'grunweg', 'vihdzp']	nobody	95-37040 3 months ago	unknown	unknown
8102	miguelmarco author:miguelmarco	feat(Tactic): add `unify_denoms` and `collect_signs` tactics	This PR adds four new tactics: - `unify_denoms` tries to put expressions with several divisions in a form with only one division. In the case of fields, it works similarly to `field_simp`, but if the hypothesis about denominators being nonzero are not present, it assumes them, and leaves them as new goals to prove. In that sense, it is an "unsafe" tactic (but can be useful nevertheless, for example when you can't find which exact hypothesis is missing). It also works with expressions of naturals and Euclidean domains, assuming the corresponding hypothesis about the denominators dividing the numerators. - `unify_denoms!` extends `unify_denoms` to work with (in)equalities, assuming also that the denominators, once in normal form, are positive. - `collect_signs` works similarly with expressions using sums and substractions: it tries to put them in a form of one sum minus other sum. In the case of working with naturals, it assumes that we never substract a bigger number from a smaller one. Both are implemented essentially as a macro that combines several rewriting rules. Some new lemmas with the corresponding rules are added. ---	please-adopt new-contributor merge-conflict modifies-tactic-syntax good first issue t-meta	407/0	Mathlib.lean,Mathlib/Algebra/EuclideanDomain/Basic.lean,Mathlib/Tactic.lean,Mathlib/Tactic/CollectSigns.lean,Mathlib/Tactic/UnifyDenoms.lean,MathlibTest/unify_denoms.lean,scripts/noshake.json	7	55	['Paul-Lez', 'YaelDillies', 'github-actions', 'joneugster', 'kbuzzard', 'mathlib4-merge-conflict-bot', 'miguelmarco']	nobody	95-3812 3 months ago	unknown	unknown
35603	2500223210-max author:2500223210-max	feat(GroupTheory/Frattini): add more theorems	Add some contents about frattini subgroup into Mathlib GroupTheory Frattini.lean,including * (convenient lemma)A subgroup contained in all maximal subgroup is contained in the FRattini subgroup * A subgroup (say H) has a proper complement (meaning for some proper subgroup K, K and H generate the whole group)if and only if it is not contained in the Frattini subgroup. * A group is cyclic iff its Frattini factor(the quotient group wrt Frattini subgroup) is cyclic. * The Frattini factor of a finite p-group is elementary abelian(that is,an abelian group G with Gᵖ={1}) * A finite p-group has trivial Frattini subgroup iff the group is elementary abelian. * Burnside theorem of Frattini factor of finite p-group. ---	new-contributor t-group-theory large-import awaiting-author	764/1	Mathlib/GroupTheory/Frattini.lean	1	3	['github-actions', 'tb65536']	nobody	95-1493 3 months ago	unknown	unknown
33791	PhoenixIra author:PhoenixIra	feat: Generalization of FixedPointApproximants to CompletePartialOrder	--- This PR provides a generalization of FixedPointApproximants to CompletePartialOrder. Not every theorem can be generalized, as sometimes we require additional conditions (namely `x ≤ f x`) in order to guarantee that the set is directed and thus the supremum is well-defined. This is not necessary in a CompleteLattice. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-order merge-conflict	223/100	Mathlib/Order/CompletePartialOrder.lean,Mathlib/SetTheory/Ordinal/FixedPointApproximants.lean	2	21	['PhoenixIra', 'github-actions', 'mathlib-merge-conflicts', 'vihdzp']	PhoenixIra and vihdzp assignee:PhoenixIra assignee:vihdzp	94-66197 3 months ago	94-66197 94 days ago	38-9880 38 days
35857	AlexeyMilovanov author:AlexeyMilovanov	feat(Logic.Equiv.BijectiveBase2): add bijective base-2 numeration	This PR introduces a formalization of the bijective base-2 numeration system. Unlike standard binary representation, bijective base-2 avoids the "leading zeros" problem, providing a strict mathematical bijection between natural numbers (`ℕ`) and lists of booleans (`List Bool`). Main additions: * `Equiv.BijectiveBase2.toBits`: Encodes `ℕ` to `List Bool`. * `Equiv.BijectiveBase2.ofBits`: Decodes `List Bool` to `ℕ`. * `equivBijectiveBase2`: The formal `ℕ ≃ List Bool` equivalence. --- Zulip: [#PR reviews > PR #35857: Bijective Base-2 Numeration](https://leanprover.zulipchat.com/#narrow/channel/144837-PR-reviews/topic/PR.20.2335857.3A.20Bijective.20Base-2.20Numeration/with/576336540) Zulip: [#batteries > Upstreaming Nat.Bits](https://leanprover.zulipchat.com/#narrow/channel/348111-batteries/topic/Upstreaming.20Nat.2EBits/with/580736051) (Note: This replaces my previously closed PR to avoid the terminology clash between "Dyadic" and dyadic rationals. The namespace and definitions have been updated accordingly). (Note: Used AI to assist with standardizing proof structures).	t-logic new-contributor LLM-generated blocked-by-batt-PR	95/0	Mathlib.lean,Mathlib/Logic/Equiv/ListNatBijective.lean	2	6	['AlexeyMilovanov', 'SnirBroshi', 'github-actions', 'joneugster']	nobody	94-62268 3 months ago	67-12091 67 days ago	27-59249 27 days
35376	michaellee94 author:michaellee94	feat(Geometry/Manifold): orientable manifolds	--- - [x] depends on: #33189 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor WIP t-differential-geometry merge-conflict awaiting-author	2116/11	Mathlib.lean,Mathlib/Geometry/Manifold/Instances/MoebiusBand.lean,Mathlib/Geometry/Manifold/Instances/Real.lean,Mathlib/Geometry/Manifold/IsManifold/ExtChartAt.lean,Mathlib/Geometry/Manifold/IsManifold/InteriorBoundary.lean,Mathlib/Geometry/Manifold/Orientation.lean,Mathlib/Topology/Closure.lean	7	8	['Rida-Hamadani', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	93-56473 3 months ago	unknown	unknown
35734	mkaratarakis author:mkaratarakis	feat(NumberTheory): matrix bounds and Siegel's lemma application for Gelfond-Schneider	This PR is the second component in the formalization of the Gelfond-Schneider Theorem (Hilbert's Seventh Problem), establishing the transcendence of $\alpha^\beta$. Building on the algebraic setup from the previous PR #35733, this file establishes analytical bounds on the linear system matrix and applies Siegel's Lemma (Lemma 8.2) to extract a bounded, non-trivial integer solution vector. We establish the exact upper bounds required to construct the auxiliary integer function $R(x)$. `c₃` and Matrix Bounds (`house_matrixA_le`)*: We define the bounding constant $c_3$, which aggregates the base bounds $c_2$ and the maximal houses of the algebraic preimages $\alpha', \beta', \gamma'$. Through extensive algebraic manipulation, we formally prove that the house of the entries in our linear system matrix $A$ is strictly bounded by $c_3^n n^{(n - 1) / 2}$. Using the bounds established above, we apply `house.exists_ne_zero_int_vec_house_le` (a formalization of Lemma 8.2, p. 490) to guarantee the existence of a non-trivial vector of algebraic integers $\eta$ in the kernel of $A$. We define the solution bounding constant $c_4$ and prove the textbook bound that the house of our resulting coefficient vector $\eta$ satisfies $\forall k, \\|\eta_k\\| \leq c_4^n * n^{(n + 1) / 2}$. - [ ] depends on: #35733 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-number-theory blocked-by-other-PR	872/5	Mathlib.lean,Mathlib/NumberTheory/NumberField/House.lean,Mathlib/NumberTheory/Transcendental/GelfondSchneider/MainAlg.lean,Mathlib/NumberTheory/Transcendental/GelfondSchneider/MainAlgSetup.lean	4	3	['github-actions', 'mathlib-dependent-issues']	nobody	93-7003 3 months ago	unknown	unknown
26013	tsuki8 author:tsuki8	feat(Data/Finset/Card,Data/Set/Finite/Basic): TODO needs a better title	add `card_bijOn` and `finset_subset_preimage_of_finite_image` Add `card_bijOn`: proves that for a bijection between finsets, their cardinalities are equal Add `finset_subset_preimage_of_finite_image`: constructs a finset subset preserving image cardinality Co-authored-by: Junyu Guo --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-data new-contributor	15/0	Mathlib/Data/Finset/Card.lean,Mathlib/Data/Set/Finite/Basic.lean	2	6	['Ruben-VandeVelde', 'github-actions', 'mathlib-merge-conflicts']	nobody	92-41208 3 months ago	unknown	unknown
35805	adrianmartir author:adrianmartir	feat(NumberTheory/Divisors): Add `infinite_setOf_divisors_iff`	This proves that the set of divisors `{ m \| m \| n }` of a natural number `n` is infinite if and only if `n` is zero. The first proof draft was by @Aristotle-Harmonic. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor awaiting-author	10/0	Mathlib/NumberTheory/Divisors.lean	1	6	['adrianmartir', 'alexjbest', 'github-actions', 'tb65536']	tb65536 assignee:tb65536	92-18534 3 months ago	68-84274 68 days ago	27-12527 27 days
35442	dhyan-aranha author:dhyan-aranha	feat: Affine line with doubled origin counter example	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor awaiting-author t-algebraic-geometry	305/0	Counterexamples.lean,Counterexamples/AffineLineWithDoubledOrigin.lean,Mathlib/AlgebraicGeometry/Limits.lean,Mathlib/Topology/Category/TopCat/Limits/Pullbacks.lean	4	21	['BryceT233', 'chrisflav', 'dhyan-aranha', 'github-actions']	nobody	92-14138 3 months ago	105-2143 105 days ago	0-3308 55 minutes
29713	jessealama author:jessealama	feat(Algebra/Homology): add Euler–Poincaré formula	This PR builds on the generalized Euler characteristic framework from #31121 to prove the Euler-Poincaré formula for chain complexes. PR #31121 defines the Euler characteristic for general homological complexes. This PR specializes those definitions to ℤ-indexed chain complexes and proves the main Euler-Poincaré theorem. ### Main result (in `EulerPoincare.lean`) * `ChainComplex.eulerChar_eq_homologyEulerChar`: For ℤ-indexed bounded chain complexes of finite-dimensional modules over a division ring, the alternating sum of chain dimensions equals the alternating sum of homology dimensions. ### Supporting lemmas The file also provides dimension lemmas generalized to arbitrary `HomologicalComplex (ModuleCat k) c` (not just ℤ-indexed chain complexes): * `HomologicalComplex.dFrom_zero_range` / `dTo_zero_range`: zero range when the target/source object is zero * `HomologicalComplex.dFrom_range_finrank_eq_d` / `dTo_range_finrank_eq_d`: range of `dFrom`/`dTo` has the same dimension as the underlying differential * `HomologicalComplex.range_dTo_le_ker_dFrom`: range of `dTo` is contained in the kernel of `dFrom` --- - [ ] depends on: #38483 (`Antiperiodic.sum_Ico_shift` and bilinear cancellation lemma) Builds on: #31121 Related to: #29639, #29643, #29646	awaiting-author t-algebra new-contributor blocked-by-other-PR label:t-algebra$	428/0	Mathlib.lean,Mathlib/Algebra/BigOperators/Periodic.lean,Mathlib/Algebra/Homology/EulerPoincare.lean	2	26	['github-actions', 'jessealama', 'joelriou', 'kim-em', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'mathlib4-merge-conflict-bot']	nobody	92-9462 3 months ago	220-24634 220 days ago	35-25302 35 days
28286	bwangpj author:bwangpj	feat(Geometry/Manifold/ContMDiff): basic lemmas for analytic (`C^ω`) functions	Add basic lemmas relating `ContMDiff` in the `C^ω` case to being `Analytic` on charts. This is upstreamed from [https://github.com/girving/ray](https://github.com/girving/ray). Co-authored-by: Geoffrey Irving --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-differential-geometry new-contributor	36/0	Mathlib/Geometry/Manifold/ContMDiff/Defs.lean	1	14	['bwangpj', 'girving', 'github-actions', 'grunweg', 'kbuzzard', 'mathlib-merge-conflicts', 'sgouezel']	sgouezel assignee:sgouezel	91-26676 2 months ago	266-23026 266 days ago	22-77793 22 days
34138	pfaffelh author:pfaffelh	feat(MeasureTheory): Introduce `DiscreteMeasure α` giving rise to a `Measure α` as a sum of `dirac`s	Define `DiscreteMeasure α` as a structure with `weight : α → ℝ≥0∞` Define `toMeasure (w : DiscreteMeasure α) : Measure α` as a sum of diracs Show properties of the resulting objects This PR intends to start a more userfriendly interaction with discrete probability (measure) theory, in contrast to probability mass functions (`PMF`). There are two main differences between `DiscreteMeasure` and `PMF`: * Every `PMF` hast the additional property `HasSum 1`, making the resulting measure a probability measure. (For `DiscreteMeasure`, I intend to use the typeclass `IsProbabilityMeasure`in a later PR instead.) * The `toMeasure` function of `MassFunction` defines the measure as a sum of diracs, which immediately makes computations possible. Discussion thread on [zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/PMF.20Refactor.3A.20FunLike.20vs.20Definition.20Change) - depends on: #37060 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-measure-probability new-contributor	224/0	Mathlib.lean,Mathlib/Algebra/GroupWithZero/Indicator.lean,Mathlib/Data/Set/Pairwise/Basic.lean,Mathlib/MeasureTheory/Measure/DiscreteMeasure.lean	4	27	['DavidLedvinka', 'eric-wieser', 'github-actions', 'mathlib-merge-conflicts', 'metakunt', 'ocfnash', 'pfaffelh']	ocfnash assignee:ocfnash	90-10906 2 months ago	43-61431 43 days ago	81-81641 81 days
34940	michaellee94 author:michaellee94	feat: the graph of a continuous function on a $C^n$ manifold is a $C^n$ manifold	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-differential-geometry new-contributor awaiting-author merge-conflict	536/0	Mathlib.lean,Mathlib/Geometry/Manifold/ChartedSpace.lean,Mathlib/Geometry/Manifold/Instances/Graph.lean,Mathlib/Geometry/Manifold/IsManifold/Basic.lean,Mathlib/Topology/Constructions/Graph.lean	5	80	['botbaki-review', 'github-actions', 'grunweg', 'mathlib-merge-conflicts', 'michaellee94', 'ocfnash']	ocfnash assignee:ocfnash	88-83336 2 months ago	90-63531 90 days ago	15-1928 15 days
35193	Brian-Nugent author:Brian-Nugent	feat(Topology/Closeds): implement category of closed sets in topological spaces	I copied over the nice API for working with `TopologicalSpace.Opens` as a category over for `TopologicalSpace.Closeds`. The only thing that did not immediately transfer was `Topology.IsInducing.functorObj` so I omitted it. Based on work of @kim-em --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor please-adopt merge-conflict awaiting-author	385/0	Mathlib.lean,Mathlib/Topology/Category/TopCat/Closeds.lean,Mathlib/Topology/Category/TopCat/Opens.lean	2	24	['Brian-Nugent', 'dagurtomas', 'github-actions', 'mathlib-merge-conflicts']	dagurtomas assignee:dagurtomas	88-82482 2 months ago	73-82555 73 days ago	17-62518 17 days
35332	yisiox author:yisiox	feat(Computability): regular expressions match a regular language	This PR adds a proof that the language matched by a regular expression is a regular language. This is achieved by the following constructions and proofs of their correctness - A DFA `epsilon` which accepts the empty language - A DFA `char (a : α)` which accepts the language containing only a single symbol - An Epsilon-NFA `concat (M₁ : εNFA α σ₁) (M₂ : εNFA α σ₂)` which accepts the concatenation of the languages of two Epsilon-NFAs - An Epsilon-NFA `kstar (M : εNFA α σ)` which accepts the Kleene star of a language of an Epsilon-NFA The following theorems on closure are added - `IsRegular.zero` - `IsRegular.one` - `IsRegular.top` - `IsRegular.singleton` - `IsRegular.mul` - `IsRegular.kstar` which demonstrates - `IsRegular.matches` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-computability new-contributor	475/0	Mathlib/Computability/DFA.lean,Mathlib/Computability/EpsilonNFA.lean	2	2	['github-actions']	nobody	88-72443 2 months ago	unknown	unknown
36210	vbeffara author:vbeffara	feat(Combinatorics/SimpleGraph): definitions of graph contraction and graph minor	A contraction is the image of a graph through a surjective function with connected fibers, and a minor is a contraction of a subgraph. This PR shows that being a contraction is transitive, but does not show the same for minors because the proof is more involved, it will be in a subsequent PR. The definitions are in `Prop` and do not contain data, but I'm not sure if that was the right choice. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor awaiting-author	151/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Contraction.lean,Mathlib/Combinatorics/SimpleGraph/Minor.lean	3	8	['YaelDillies', 'github-actions', 'mathlib-merge-conflicts', 'robin-carlier', 'vbeffara']	b-mehta assignee:b-mehta	88-55013 2 months ago	34-83676 34 days ago	53-31808 53 days
14313	grhkm21 author:grhkm21	feat(RepresentationTheory/FdRep): FdRep is a full subcategory of Rep	``` /-- Equivalence between `FDRep` and the full subcategory of finite dimensional `Rep`. -/ def equivFiniteDimensional : FDRep k G ≌ FullSubcategory (fun V : Rep k G ↦ FiniteDimensional k V) ```	merge-conflict t-algebra t-category-theory new-contributor label:t-algebra$	47/8	Mathlib/RepresentationTheory/FDRep.lean	1	21	['fpvandoorn', 'github-actions', 'grhkm21', 'joelriou', 'kim-em', 'mathlib-bors']	nobody	88-9502 2 months ago	unknown	unknown
33592	nielstron author:nielstron	feat(Computability/ContextFreeGrammar): mapping between two types of nonterminal symbols	This PR picks up https://github.com/leanprover-community/mathlib4/pull/15895 and resolves the failing lemma by redefining Good symbols. --- I checked that https://github.com/leanprover-community/mathlib4/pull/13514 builds correctly when based on this build. PR for that is #33599 This is my first contribution please let me know of any changes I should outline. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-computability new-contributor	160/0	Mathlib/Computability/ContextFreeGrammar.lean	1	34	['YaelDillies', 'github-actions', 'madvorak', 'nielstron']	nobody	87-84870 2 months ago	unknown	unknown
35144	daniel-carranza author:daniel-carranza	feat(CategoryTheory/Enriched): tensor product of enriched categories	For a braided monoidal category `V`, defines the tensor product of `V`-categories `C` and `D`, and shows that the type of `V`-functors out of the tensor product `C \times D` is equivalent to the type of "enriched bifunctors" `EnrichedBifunctor V C D`. --- This work originates from infinity-cosmos project, where it is used to formalize the notion of cotensors in an enriched category. There are some additional coherence lemmas in a braided monoidal category which have been added. Currently, line 209 violates the style guideline that terminal simp calls should not be squeezed. When I tried to replace this with a single `simp`, I get an error message: `maximum recursion depth has been reached`. Any suggestions (either with this or anything else) are greatly appreciated - thank you! [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-category-theory infinity-cosmos awaiting-author	333/0	Mathlib.lean,Mathlib/CategoryTheory/Enriched/TensorProductCategory.lean,Mathlib/CategoryTheory/Monoidal/Braided/Basic.lean	3	12	['daniel-carranza', 'emilyriehl', 'github-actions', 'joelriou', 'robin-carlier']	nobody	87-80577 2 months ago	unknown	unknown
34236	homeowmorphism author:homeowmorphism	feat(GroupTheory/FinitelyPresentedGroup): add finitely presented groups	Formulation of finitely presented groups feat(GroupTheory/FinitelyPresentedGroup): add finitely presented groups We define the notion of `IsFinitelyPresented` with equivalent datatype notions, what it means for a subgroup to be finitely generated in the normal closure, and some instances of finitely presented groups. This started as an ItaLean2025 project. The related Zulip thread is here: https://leanprover.zulipchat.com/#narrow/channel/541885-ItaLean-2025/topic/Projects.3A.20Finitely.20Presented.20Groups/with/567565752. Use of AI: * Aristotle was used for giving a preliminary proof of some statements as this is my first contribution and I wanted to understand how to prove things; they have since been changed. * GPT-5.2 was used to generate some of the proof sub-statements for efficiency once the mathematical blueprints of the proofs have been worked out. * GPT-5.3 was used to rapidly refactor the code. Human review by PR author in-progress, but got to a point where it would be good to get external input. * GPT-5.4 was used to refactor the variables. Human PR author then rewrote the whole thing. --- - [x] depends on: #34580 - [x] depends on: #34624 - [x] depends on: #35033 - [x] depends on: #35029 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-group-theory new-contributor merge-conflict blocked-by-other-PR	459/3	Mathlib.lean,Mathlib/GroupTheory/FinitelyPresentedGroup.lean	5	72	['copilot-pull-request-reviewer', 'eric-wieser', 'github-actions', 'grunweg', 'homeowmorphism', 'kbuzzard', 'mathlib-bors', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'tb65536']	nobody	87-78863 2 months ago	74-61861 74 days ago	0-4449 1 hour
27226	xcloudyunx author:xcloudyunx	feat(Combinatorics/SimpleGraph): Add Subgraph.inclusion_edge_apply_coe and inclusion_edgeSet_apply_coe	This PR continues the work from #25248. Original PR: https://github.com/leanprover-community/mathlib4/pull/25248	awaiting-author t-combinatorics new-contributor merge-conflict	14/0	Mathlib/Combinatorics/SimpleGraph/Subgraph.lean	1	4	['b-mehta', 'github-actions', 'mathlib-merge-conflicts', 'xcloudyunx']	b-mehta assignee:b-mehta	87-71970 2 months ago	294-52116 294 days ago	25-82514 25 days
33688	Citronhat author:Citronhat	feat(PMF): add expectation lemmas for Poisson PMF	This PR adds some basic results about the Poisson distribution, its `PMF`, and its expectation. New lemmas: * `poissonPMF_apply` — an unfolding lemma for `poissonPMF`. * `poissonPMFReal_mul_eq_succ_mul` — the standard recursion identity for the Poisson mass function. * `poissonPMFReal_hasSum_nmul` — shows that `fun n ↦ poissonPMFReal r n * n` has sum `r`. * `poissonPMF_tsum_nmul` — the corresponding identity at the level of the `PMF`. * `poissonPMF_coe_tsum_nmul` — the same result after coercion to `ℝ`. Both `ℝ`-valued and `ℝ≥0∞`-valued formulations are included so that these results can be used conveniently in both Lebesgue and Bochner integration contexts.	new-contributor t-measure-probability awaiting-author merge-conflict	21/0	Mathlib/Probability/Distributions/Poisson.lean	1	11	['Citronhat', 'DavidLedvinka', 'github-actions', 'mathlib-merge-conflicts', 'urkud']	urkud assignee:urkud	87-53950 2 months ago	98-68599 98 days ago	47-75960 47 days
34005	MSpill author:MSpill	feat: inverse function theorem for manifolds (concrete version)	Proves the inverse function theorem for manifolds: given manifolds $M, N$ and a $C^n$ map $f : M \to N$ whose differential is a linear isomorphism at $p \in M$, then $f$ is a local diffeomorphism at $p$, provided that both $p$ and its image are interior points. The proof proceeds in 4 main steps: 1. Define composition of partial diffeomorphisms 2. Show that the extended chart at an interior point can be restricted to an open set on which it is a partial diffeomorphism, viewing the model vector space as a manifold modelled on itself trivially 3. Use the inverse function theorem (applied to $f$ written in coordinates) to obtain a partial diffeomorphism between model vector spaces 4. Compose with chart diffeomorphisms to obtain a partial diffeomorphism between the manifolds. ------ [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author t-differential-geometry new-contributor merge-conflict	232/3	Mathlib/Geometry/Manifold/LocalDiffeomorph.lean	1	12	['MSpill', 'github-actions', 'grunweg', 'mathlib-merge-conflicts']	grunweg assignee:grunweg	87-53705 2 months ago	unknown	unknown
34830	parabamoghv author:parabamoghv	feat(CategoryTheory/Monoidal): add definition of categorical groups	This PR defines of categorical groups, also known as coherent 2-groups, in mathlib. Motivation: Categorical groups are well-studied structures in monoidal category theory, but are not currently available in mathlib. The definitions in this PR follow the existing design patterns used for Category, MonoidalCategory, and BraidedCategory. This PR focuses on setting up the core structure and notation. Basic lemmas and further developments will be provided in a subsequent PR. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-category-theory new-contributor WIP merge-conflict	163/0	Mathlib.lean,Mathlib/CategoryTheory/Monoidal/CategoricalGroups/Basic.lean	2	27	['dagurtomas', 'github-actions', 'mathlib-merge-conflicts', 'parabamoghv', 'robin-carlier']	robin-carlier assignee:robin-carlier	87-42425 2 months ago	102-24465 102 days ago	5-9355 5 days
36313	SproutSeeds author:SproutSeeds	feat(Inversion): cobounded tendsto near center	Part of #5939 Add `tendsto_inversion_nhdsNE_center_cobounded` in `Mathlib/Geometry/Euclidean/Inversion/Basic.lean`, proving `Tendsto (inversion c R) (𝓝[≠] c) (Bornology.cobounded P)` for `R ≠ 0`. Tools used: Codex 5.3 extra high --- Happy to adjust naming, placement, or proof style based on maintainer preference.	t-euclidean-geometry new-contributor LLM-generated awaiting-author	42/0	Mathlib/Geometry/Euclidean/Inversion/Basic.lean	1	11	['SproutSeeds', 'euprunin', 'github-actions', 'jsm28', 'kbuzzard', 'ocfnash']	jsm28 assignee:jsm28	87-17140 2 months ago	unknown	unknown
36323	SproutSeeds author:SproutSeeds	feat(Inversion): discontinuity and center/global fderiv formulas	Part of #5939 Adds the discontinuity-at-center lemma for inversion and derives the center/global `fderiv` formulas from it. This draft currently builds on the preceding cobounded-tendsto lemma from #36313 while that earlier slice is under review. Scope is limited to `Mathlib/Geometry/Euclidean/Inversion/Calculus.lean`. Tools used: Codex 5.3 extra high --- Happy to adjust naming, placement, or proof style based on maintainer preference.	t-euclidean-geometry new-contributor LLM-generated	65/0	Mathlib/Geometry/Euclidean/Inversion/Basic.lean,Mathlib/Geometry/Euclidean/Inversion/Calculus.lean	2	2	['github-actions']	nobody	86-79751 2 months ago	unknown	unknown
36326	Arnav-panjla author:Arnav-panjla	Feat/gaussian schwartz map	feat(Analysis/SpecialFunctions/Gaussian): define the Gaussian as a Schwartz function in 1D Define the Gaussian function `x ↦ exp (-x^2)` as a `SchwartzMap` in the one-dimensional case. The proof establishes the Schwartz decay conditions by showing that polynomially weighted expressions of the form `(1 + x^2)^m * exp (-x^2)` are bounded. This allows the Gaussian to be packaged using the `SchwartzMap` API. During the implementation a few adjustments were required to match the current Mathlib API. In particular: * replace the non-existent `IsBigO.mul_right` with `IsBigO.of_bound` applied to the full product `(1 + x^2)^m * exp (-x^2)` * fix `mem_cocompact` usage by replacing `(hh_tendsto.eventually ...).mem_cocompact` with `mem_cocompact.mp (hh_tendsto ...)` * adjust the `hb_bound` step using `gcongr` with exact bounds so that both goals close * remove the unused declaration `hf_nonpos` * register the required import in `Mathlib.lean` This implements the one-dimensional case mentioned in the issue. The generalization to Gaussians associated with arbitrary positive-definite bilinear forms can be added in a follow-up PR. Closes #33072	t-analysis new-contributor	235/0	Mathlib.lean,Mathlib/Analysis/SpecialFunctions/Gaussian/SchwartzMap.lean	2	4	['CoolRmal', 'github-actions']	nobody	86-73078 2 months ago	unknown	unknown
33668	Citronhat author:Citronhat	feat(PMF): add lintegral formulas for PMF	This PR introduces two lemmas describing the `lintegral` of a function with respect to the measure induced by a probability mass function: - `PMF.lintegral_eq_tsum` - `PMF.lintegral_eq_sum` These are the `ℝ≥0∞` analogues of the existing Bochner `integral` formulas `integral_eq_tsum` and `integral_eq_sum`. They could be useful for reasoning about expectations and integrability. In addition, the proof of `integral_eq_sum` is simplified by deriving it directly from `integral_eq_tsum` using `tsum_fintype`.	t-measure-probability new-contributor awaiting-author merge-conflict	14/5	Mathlib/Probability/ProbabilityMassFunction/Integrals.lean	1	3	['DavidLedvinka', 'github-actions', 'mathlib-merge-conflicts']	nobody	84-66880 2 months ago	91-15223 91 days ago	55-71727 55 days
36387	FrankieeW author:FrankieeW	feat(NumberTheory/QuadraticField): parameter uniqueness for quadratic fields	## Summary Prove that every quadratic field `ℚ(√d)` can be normalized to have a squarefree integer parameter, and that this parameter is unique. ## Main Results - `Qsqrtd.rescale`: rescaling isomorphism `ℚ(√d) ≃ₐ[ℚ] ℚ(√(a²d))` for `a ≠ 0` - `Qsqrtd_iso_int_param`: every `ℚ(√d)` is isomorphic to one with an integer parameter - `Qsqrtd_iso_squarefree_int_param`: every `ℚ(√d)` is isomorphic to one with a squarefree integer parameter - `Qsqrtd.param_unique`: if `ℚ(√d₁) ≃ₐ[ℚ] ℚ(√d₂)` with both `d₁, d₂` squarefree and `≠ 1`, then `d₁ = d₂` ## Helper Lemmas - `squarefree_eq_of_rat_sq_mul`: if `d₁ = d₂ · r²` with both squarefree, then `d₁ = d₂` - `int_dvd_of_ratio_square`: if `d₁/d₂` is a rational square and `d₂` is squarefree, then `d₂ ∣ d₁` - `not_isSquare_neg_one_rat`: `-1` is not a square in `ℚ` --- - [ ] depends on: #36347	WIP t-number-theory blocked-by-other-PR new-contributor large-import LLM-generated	400/0	Mathlib.lean,Mathlib/Algebra/QuadraticAlgebra/Defs.lean,Mathlib/Algebra/Squarefree/Basic.lean,Mathlib/NumberTheory/QuadraticField/Basic.lean	4	4	['FrankieeW', 'github-actions', 'mathlib-dependent-issues']	nobody	84-43487 2 months ago	unknown	unknown
35058	GrigorenkoPV author:GrigorenkoPV	chore: move tendsto_{floor,ceil}_at{Top,Bot}	Moves: - Topology.Algebra.Order.Floor.tendsto_floor_atTop -> Order.Filter.AtTopBot.Floor.tendsto_floor_atTop - Topology.Algebra.Order.Floor.tendsto_floor_atBot -> Order.Filter.AtTopBot.Floor.tendsto_floor_atBot - Topology.Algebra.Order.Floor.tendsto_ceil_atTop -> Order.Filter.AtTopBot.Floor.tendsto_ceil_atTop - Topology.Algebra.Order.Floor.tendsto_ceil_atBot -> Order.Filter.AtTopBot.Floor.tendsto_ceil_atBot --- Tracked in #7987 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor large-import awaiting-author	22/25	Mathlib/Order/Filter/AtTopBot/Floor.lean,Mathlib/Topology/Algebra/Order/Floor.lean	2	3	['GrigorenkoPV', 'github-actions', 'j-loreaux']	nobody	83-58708 2 months ago	unknown	unknown
31670	edwin1729 author:edwin1729	feat(Topology/Order): Scott Topology is Sober over Algebraic DCPO	--- [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/.3E.20Algebraic.20complete.20partial.20order.20and.20domain.20theory/with/536359313) here (2/2) PR to prove result in Stone Duality. Here we prove that Scott Topologies over Algebraic DCPOs are sober. - [ ] depends on: #31662 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology blocked-by-other-PR new-contributor merge-conflict	510/1	Mathlib.lean,Mathlib/Topology/Order/ScottTopology.lean,Mathlib/Topology/Order/ScottTopologyDCPO.lean,docs/references.bib	4	5	['github-actions', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	83-56590 2 months ago	unknown	unknown
36463	AlexeyMilovanov author:AlexeyMilovanov	feat(Data.Nat.Bits): add Nat.ofBits and prove bits_injective	This PR introduces `Nat.ofBitsList` for `List Bool` and provides the missing proofs that the standard binary representation `Nat.bits` is injective (`Nat.bits_injective`) and possesses a right inverse for normalized lists (`Nat.bits_ofBitsList`). `ofBitsList` is implemented as an `abbrev` using `foldr` (keeping it transparent to tactics like `simp`). It serves as the exact left inverse to `bits`. Furthermore, `bits_ofBitsList` establishes that `bits` and `ofBitsList` form a bijection between `ℕ` and the set of lists with no trailing `false` values. This avoids the name collision with `Nat.ofBits` from `Batteries` and aligns with previous Zulip discussions (see [here](https://leanprover.zulipchat.com/#narrow/channel/144837-PR-reviews/topic/PR.20.2335857.3A.20Bijective.20Base-2.20Numeration)) regarding the utility of having a complete list-based API for `Nat.bits` in the library. CC: @linesthatinterlace - Adds `Nat.ofBitsList` (as an `abbrev`) - Adds `Nat.ofBitsList_bits` (left inverse property) - Adds `Nat.bits_injective` - Adds `Nat.ofBitsList_eq_zero_iff` (helper lemma for lists without trailing zeros) - Adds `Nat.bits_ofBitsList` (right inverse property) --- Zulip: [#PR reviews > PR #35857: Bijective Base-2 Numeration](https://leanprover.zulipchat.com/#narrow/channel/144837-PR-reviews/topic/PR.20.2335857.3A.20Bijective.20Base-2.20Numeration/with/576336540) Zulip: [#batteries > Upstreaming Nat.Bits](https://leanprover.zulipchat.com/#narrow/channel/348111-batteries/topic/Upstreaming.20Nat.2EBits/with/580736051)	t-data new-contributor awaiting-author blocked-by-batt-PR	68/1	Mathlib/Data/Nat/Bits.lean	1	5	['github-actions', 'joneugster', 'linesthatinterlace']	nobody	83-41826 2 months ago	73-80146 73 days ago	9-55375 9 days
35684	spitters author:spitters	feat(CategoryTheory/MarkovCategory): Kleisli PMF is a Markov category	Add `Mathlib/CategoryTheory/MarkovCategory/KleisliPMF.lean` showing that `KleisliCat PMF` is a `MarkovCategory`. Uses `Prod` as tensor and `PUnit` as unit; reuses Mathlib's existing `KleisliCat`, `LawfulMonad PMF`, and `MarkovCategory` infrastructure. Builds the full instance stack: MonoidalCategory → BraidedCategory → SymmetricCategory → CopyDiscardCategory → MarkovCategory --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-category-theory new-contributor awaiting-author merge-conflict	323/1	Mathlib.lean,Mathlib/CategoryTheory/MarkovCategory/KleisliPMF.lean,Mathlib/Tactic/Linter/DirectoryDependency.lean	3	6	['dagurtomas', 'github-actions', 'mathlib-merge-conflicts', 'spitters']	nobody	83-31706 2 months ago	95-63951 95 days ago	2-35223 2 days
35738	GrigorenkoPV author:GrigorenkoPV	perf: remove some `aesop`s and `grind`s	--- Needs benchmarking. After that I can split it into several smaller portions, if needed. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor awaiting-author merge-conflict	236/92	Mathlib/Data/Finset/Card.lean,Mathlib/Data/Rel.lean,Mathlib/Data/Set/Lattice/Image.lean,Mathlib/Data/Set/Prod.lean,Mathlib/Logic/Equiv/Prod.lean,Mathlib/Order/Interval/Finset/Basic.lean,Mathlib/Order/KrullDimension.lean,Mathlib/Order/SupIndep.lean	8	7	['github-actions', 'mathlib-merge-conflicts', 'themathqueen', 'vihdzp']	nobody	83-31705 2 months ago	97-13385 97 days ago	0-45482 12 hours
36503	Mrigna01 author:Mrigna01	Add false theorem test file	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor	135/0	Mathlib/FalseBench/FalseTheorems.lean	1	3	['github-actions']	nobody	82-54988 2 months ago	unknown	unknown
14603	awueth author:awueth	feat: degree is invariant under graph isomorphism	--- Mathlib has the definition `SimpleGraph.Iso.mapNeighborSet` which is an equivalence between neighbor sets induced by an isomorphism. Would it be beneficial to add the same equivalence for `neighborFinset`? [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-combinatorics new-contributor	24/0	Mathlib/Combinatorics/SimpleGraph/Map/Finite.lean	1	12	['SnirBroshi', 'awueth', 'github-actions', 'jcommelin', 'kim-em', 'urkud']	nobody	82-36386 2 months ago	unknown	unknown
33599	nielstron author:nielstron	feat(Computability/ContextFreeGrammar): closure under union	--- This PR picks up https://github.com/leanprover-community/mathlib4/pull/13514 and resolves the outstanding errors. - [ ] depends on: #33592 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	blocked-by-other-PR t-computability new-contributor	498/0	Mathlib/Computability/ContextFreeGrammar.lean	1	2	['github-actions', 'mathlib4-dependent-issues-bot']	nobody	82-19823 2 months ago	137-28682 137 days ago	10-62063 10 days
9605	davikrehalt author:davikrehalt	feat(Data/Finset & List): Add Lemmas for Sorting and Filtering	This PR includes several useful lemmas to the Data/Finset and Data/List modules in Lean's mathlib: 1. `toFinset_filter` (List): Shows that filtering commutes with toFinset. 2. `toFinset_is_singleton_implies_replicate` (List): Shows a list with a singleton toFinset is a List.replicate. 3. `filter_sort_commute` (Finset): Sorting and filtering can be interchanged in Finsets. 4. `Sorted.filter` (List): A sorted list stays sorted after filtering. 5. `Sorted.append_largest` (List): Appending the largest element keeps a list sorted. 6. `sort_monotone_map` (Finset): Relates sorting of a Finset after mapping to sorting of a list. 7. `sort_insert_largest` (Finset): Sorting a Finset with an inserted largest element. 8. `sort_range` (Finset): Sorting a range in a Finset equals the corresponding range list. 9. ~~`filter_eval_true` (List): Filtering a list with a predicate always true keeps the list unchanged.~~ 10. ~~`filter_eval_false` (List): Filtering with an always-false predicate gives an empty list.~~ 11. ~~`pairwise_concat` (List): Iff condition for Pairwise relation in concatenated lists (similar to pairwise_join).~~ 12. `list_map_toFinset` (Finset): toFinset commutes with map under injection --- - [x] depends on: #15952 This is my first PR to mathlib, so I'm not too familiar with etiquette's and more specifically there are two proofs in the PR which uses aesop, and I am not sure if it's frowned upon. I kept the aesop in there for now as I couldn't construct very short proofs otherwise. The sort_range function proof was suggested in https://leanprover.zulipchat.com/#narrow/stream/113489-new-members/topic/Computing.20Finset.20sort.20of.20Finset.20range/near/410346731 by Ruben Van de Velde. Thanks for your time for improving this PR.	please-adopt t-data new-contributor merge-conflict awaiting-author	71/0	Mathlib/Data/Finset/Basic.lean,Mathlib/Data/Finset/Image.lean,Mathlib/Data/Finset/Sort.lean,Mathlib/Data/List/Sort.lean	4	30	['YaelDillies', 'davikrehalt', 'eric-wieser', 'github-actions', 'jcommelin', 'urkud', 'vihdzp']	nobody	82-19279 2 months ago	unknown	unknown
35652	dennj author:dennj	feat(LinearAlgebra/Matrix): add `Matrix.mul_eq_smul_one_symm`	Adds three lemmas: - IsLeftRegular.mul_eq_of_comm (Algebra/Group/Defs.lean): if a is left-regular, a * b = c, and c commutes with a, then b * a = c. Generalises IsLeftRegular.mul_eq_one_symm from the c = 1 case. - IsRightRegular.mul_eq_of_comm: symmetric version. - mul_eq_smul_one_symm (Algebra/Group/Action/Defs.lean): scalar variant of mul_eq_one_symm. For a monoid β with a compatible scalar action by α, if a * b = c • 1 and a is left-regular, then b * a = c • 1. Proven in one line via IsLeftRegular.mul_eq_of_comm, since c • 1 is central thanks to IsScalarTower α β β and SMulCommClass α β β. The additive analogues are produced by to_additive. The general mul_eq_of_comm helpers capture the underlying pattern: "a left/right-regular element can be cancelled when the conclusion commutes with it" and are reusable beyond this PR's specialisation. Human made PR	t-algebra new-contributor LLM-generated awaiting-author label:t-algebra$	28/0	Mathlib/Algebra/Group/Action/Defs.lean,Mathlib/Algebra/Group/Defs.lean	1	7	['dagurtomas', 'dennj', 'eric-wieser', 'github-actions', 'grunweg']	ocfnash assignee:ocfnash	81-85922 2 months ago	29-55762 29 days ago	6-75243 6 days
36587	yhx-12243 author:yhx-12243	feat(Algebra/GCDMonoid): Distributive lattice structure for Associates in GCDMonoid	Add a distributive lattice structure for `Associates α` in `GCDMonoid`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor label:t-algebra$	60/3	Mathlib.lean,Mathlib/Algebra/GCDMonoid/Basic.lean,Mathlib/Algebra/GCDMonoid/DistribLattice.lean	2	2	['github-actions']	nobody	81-28100 2 months ago	unknown	unknown
35662	FrankieeW author:FrankieeW	feat(NumberTheory/Zsqrtd): add Archimedean instance via le_arch	This PR follows a suggestion made in #35606 , #35481 - add `Zsqrtd.le_arch_smul` in `Mathlib/NumberTheory/Zsqrtd/Basic.lean` - use it to provide `instance : Archimedean (ℤ√d)` in the `Nonsquare` section - refactor the proof using symmetry to reduce duplication while keeping checks clean --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor awaiting-author merge-conflict LLM-generated	46/4	Mathlib/NumberTheory/PellMatiyasevic.lean,Mathlib/NumberTheory/Zsqrtd/Basic.lean	2	13	['FrankieeW', 'MichaelStollBayreuth', 'euprunin', 'github-actions', 'mathlib-merge-conflicts', 'tb65536']	MichaelStollBayreuth assignee:MichaelStollBayreuth	81-27836 2 months ago	84-5952 84 days ago	15-49717 15 days
36119	Ruizsolveall author:Ruizsolveall	feat(Topology/Covering): fundamental group of the circle is ℤ	- Proves that the fundamental group of the circle `π₁(S¹, 0)` is isomorphic to `ℤ`, via covering space theory. - Constructs the winding number map `nLoop : ℤ → Path 0 0` on `AddCircle 1`, and proves it is surjective (`nLoop_surjective`), injective (`nLoop_homotopic_iff`), and additive (`nLoop_add`). - Assembles these into the group isomorphism `windingNumberIso : Multiplicative ℤ ≃* FundamentalGroup (AddCircle 1) 0`. ## Approach Uses the covering map `ℝ → AddCircle 1` and unique path lifting to establish the bijection between homotopy classes of loops and integers (winding numbers). Homotopy invariance of lifted endpoints gives injectivity; surjectivity follows from lifting arbitrary loops. Additivity uses path concatenation of lifts in the simply connected total space `ℝ`. ## AI disclosure I used Claude (Anthropic) to write the PR description, code comments, and to help refine code style. The proof strategy and all Lean code are my own. I understand and can vouch for all the code in this PR.	t-topology new-contributor awaiting-author LLM-generated	236/0	Mathlib.lean,Mathlib/Topology/Covering/FundamentalGroupCircle.lean	2	26	['Ruizsolveall', 'SnirBroshi', 'b-mehta', 'dagurtomas', 'github-actions', 'grunweg', 'vihdzp']	nobody	80-76463 2 months ago	81-68995 81 days ago	8-11652 8 days
36347	FrankieeW author:FrankieeW	feat(NumberTheory/QuadraticField): define quadratic number fields as QuadraticAlgebra ℚ d 0	Define `Qsqrtd d` as `QuadraticAlgebra ℚ d 0`, representing the quadratic number field `ℚ(√d)`. Prove trace and norm results, show `Qsqrtd d` is a number field and a quadratic extension when `d` is not a perfect square, and prove that `ℚ(√0)` and `ℚ(√1)` are not fields. Include `IsQuadraticField` as a predicate for quadratic extensions of `ℚ`, and bridge lemmas connecting squarefree integer parameters to the non-square condition. This PR is part of a series upstreaming the [QuadraticNumberFields](https://github.com/FrankieeW/QuadraticNumberFields) project. [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/quadratic.20number.20fields) --- ### PRs - #36347 （this PR） - #36387 ---	t-number-theory new-contributor large-import awaiting-author LLM-generated	191/0	Mathlib.lean,Mathlib/Algebra/QuadraticAlgebra/Defs.lean,Mathlib/Algebra/Squarefree/Basic.lean,Mathlib/NumberTheory/QuadraticField/Basic.lean	4	29	['FrankieeW', 'eric-wieser', 'github-actions', 'riccardobrasca', 'tb65536', 'wwylele']	tb65536 assignee:tb65536	80-50130 2 months ago	78-125 77 days ago	7-8533 7 days
35651	sun123zxy author:sun123zxy	feat(Mathlib/RingTheory/Ideal/Cotangent): `Submodule.map` definition of cotangent spaces	This PR adds an alternative definition of the cotangent space as an image under the R-module quotient map. --- Split from PR #33247 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-ring-theory new-contributor awaiting-author	47/20	Mathlib/RingTheory/Ideal/Cotangent.lean,Mathlib/RingTheory/Ideal/Quotient/Operations.lean	2	20	['chrisflav', 'erdOne', 'github-actions', 'mathlib-merge-conflicts', 'sun123zxy']	chrisflav assignee:chrisflav	80-7174 2 months ago	77-75273 77 days ago	10-2592 10 days
22314	shetzl author:shetzl	feat: add leftmost derivations for context-free grammars	Leftmost derivations are often easier to reason about than arbitrary derivations. This PR adds leftmost variants of Rewrites, Produces and Derives to the existing definition of context-free grammars and proves that a string of terminals can be derived iff it can be leftmost derived. Co-authored-by: Tobias Leichtfried --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	merge-conflict t-computability awaiting-author new-contributor	383/0	Mathlib.lean,Mathlib/Computability/LeftmostDerivation.lean	2	55	['YaelDillies', 'github-actions', 'madvorak', 'mathlib4-merge-conflict-bot', 'shetzl']	nobody	79-80629 2 months ago	unknown	unknown
31610	rudynicolop author:rudynicolop	feat(Computability/NFA): Kleene star closure for Regular Languages via NFA	This PR constructs a Kleene star closure for non-epsilon NFAs, and proves that regular languages are closed under Kleene star. The NFA construction is `NFA.kstar`. The main theorems are: - `NFA.accepts_kstar`: demonstrates that `M.kstar` accepts the Kleene star closure of the language of `M`. - `IsRegular.kstar`: demonstrates that regular languages are closed under Kleene star. There is an onging zulip discussion about regular languages in Mathlib: https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Regular.20languages.3A.20the.20review.20queue/with/553759136 This discussion is also tracked at #24205. Furthermore, the construction and proofs in this PR are heavily inspired by @TpmKranz from his #15651. #15651 supersedes this PR, so if it is accepted then this PR is not needed. --- - [x] depends on: #31038 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-computability new-contributor awaiting-author awaiting-CI	405/7	Mathlib/Computability/NFA.lean	1	16	['YaelDillies', 'ctchou', 'github-actions', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	79-80528 2 months ago	138-72910 138 days ago	43-76977 43 days
36757	alok author:alok	feat(Order/Filter): add Filter.IsFree and Filter.IsNonprincipal	## Summary Adds two filter predicates and their basic API: - `Filter.IsFree`: no point belongs to every set (`f.ker = ∅`), equivalently `f ≤ cofinite` - `Filter.IsNonprincipal`: not equal to `𝓟 s` for any set `s` Every free `NeBot` filter is non-principal (`IsFree.isNonprincipal`), but the converse fails for general filters (e.g. `𝓝 x` in a non-discrete T₁ space is non-principal but not free). For ultrafilters the two notions coincide (`Ultrafilter.isNonprincipal_iff_isFree`). On finite types, no `NeBot` filter is free (`not_isFree_of_neBot`). ## Test plan - [x] `lake build Mathlib.Order.Filter.Cofinite` passes - [x] `lake build Mathlib.Order.Filter.Ultrafilter.Basic` passes 🤖 Generated with [Claude Code](https://claude.com/claude-code)	t-order new-contributor	98/1	Mathlib/Order/Filter/Cofinite.lean,Mathlib/Order/Filter/Ultrafilter/Basic.lean	2	2	['github-actions']	nobody	77-40799 2 months ago	unknown	unknown
36825	danlyng author:danlyng	feat(MeasureTheory/Integral/IntegralEqImproper): add Iic variants of nonneg/nonpos derivative integrability and FTC-2	Add the `Iic` counterparts of the existing `Ioi` results for automatic integrability of derivatives on semi-infinite intervals and the corresponding corollaries computing the integral value. Additionally, apply minor fixes to existing docstrings. New declarations: - `integrableOn_Iic_deriv_of_nonneg` / `integrableOn_Iic_deriv_of_nonneg'` - `integrableOn_Iic_deriv_of_nonpos` / `integrableOn_Iic_deriv_of_nonpos'` - `integral_Iic_of_hasDerivAt_of_nonneg` / `integral_Iic_of_hasDerivAt_of_nonneg'` - `integral_Iic_of_hasDerivAt_of_nonpos` / `integral_Iic_of_hasDerivAt_of_nonpos'` These mirror `integrableOn_Ioi_deriv_of_nonneg`, `integrableOn_Ioi_deriv_of_nonpos`, `integral_Ioi_of_hasDerivAt_of_nonneg`, `integral_Ioi_of_hasDerivAt_of_nonpos` and their primed variants.	t-measure-probability new-contributor awaiting-author	107/9	Mathlib/MeasureTheory/Integral/IntegralEqImproper.lean	1	7	['EtienneC30', 'github-actions']	EtienneC30 assignee:EtienneC30	73-4529 2 months ago	73-4529 73 days ago	2-66204 2 days
36719	NoneMore author:NoneMore	feat(ModelTheory): add `PartialType` for first-order theories	This PR adds the definitions of partial types over theories and over parameter sets, and proves several equivalent characterizations. --- - [ ] depends on: #36667 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	blocked-by-other-PR t-logic new-contributor	468/0	Mathlib.lean,Mathlib/ModelTheory/PartialTypes.lean,Mathlib/ModelTheory/Semantics.lean,Mathlib/ModelTheory/Syntax.lean	4	5	['NoneMore', 'github-actions', 'mathlib-dependent-issues', 'vihdzp']	nobody	69-23404 2 months ago	unknown	unknown
37101	fsefzig author:fsefzig	feat: definition of kummer polynomials and prove that AdjoinRoot (KummerPolynomial n s) is etale	This defines the Kummer polynomial ` KummerPolynomial n s := X^n - s` over a ring R and constructs the following instances for `AdjoinRoot (KummerPolynomial n s)`: · Faithfullyflat · SmoothOfRelativeDimension 0 · Etale	t-ring-theory new-contributor awaiting-author	345/0	Mathlib.lean,Mathlib/RingTheory/AdjoinRootKummer.lean	2	24	['acmepjz', 'chrisflav', 'fsefzig', 'github-actions', 'vihdzp']	nobody	61-75388 2 months ago	unknown	unknown
37585	cascone26 author:cascone26	feat: formal statements of Robin's and Lagarias' inequalities equivalent to RH	## Summary This PR adds `Mathlib/NumberTheory/LSeries/RobinInequality.lean`, which contains formal Lean 4 statements of two classical equivalences of the Riemann Hypothesis: Robin's theorem (1984): RH ↔ σ₁(n) < e^γ · n · ln(ln(n)) for all n > 5040 Lagarias' theorem (2002): RH ↔ σ₁(n) ≤ H_n + exp(H_n) · ln(H_n) for all n ≥ 1 ### New declarations - `robinBound (n : ℕ) : ℝ` — the Robin bound e^γ · n · ln(ln(n)) - `lagariasBound (n : ℕ) : ℝ` — the Lagarias bound H_n + exp(H_n) · ln(H_n) - `robin_iff_RH : RiemannHypothesis ↔ ∀ n > 5040, σ₁(n) < robinBound n` - `lagarias_iff_RH : RiemannHypothesis ↔ ∀ n ≥ 1, σ₁(n) ≤ lagariasBound n` ### Status The statements are complete and use existing Mathlib primitives: - `ArithmeticFunction.sigma` for σ₁ - `Real.eulerMascheroniConstant` for γ - `harmonic` for H_n (with ℚ → ℝ coercion) - `RiemannHypothesis` from `Mathlib.NumberTheory.LSeries.RiemannZeta` The proofs are currently `sorry`. The Robin direction (RH → inequality) requires analytic number theory following Robin's original 1984 paper. The converse uses Gronwall's theorem on superior highly composite numbers. Both are substantial Mathlib projects in their own right. This PR establishes the formal statements as a foundation for future proof work. These equivalences are not currently formalized anywhere in Mathlib. ### References - G. Robin, Grandes valeurs de la fonction somme des diviseurs et hypothèse de Riemann, J. Math. Pures Appl. 63 (1984), 187–213. - J. Lagarias, An elementary problem equivalent to the Riemann hypothesis, Amer. Math. Monthly 109 (2002), 534–543. ### Note on `sorry` I'm aware Mathlib does not merge `sorry`-laden PRs in general. I'm submitting this as a draft to: 1. Get feedback on whether the statement formulation is idiomatic 2. Establish that these statements don't already exist in Mathlib under a different name 3. Invite collaboration on completing the proofs	t-number-theory new-contributor	98/0	Mathlib/NumberTheory/LSeries/RobinInequality.lean	1	2	['github-actions']	nobody	60-34153 1 month ago	unknown	unknown
36937	Yaohua-Leo author:Yaohua-Leo	feat(Algebra/Jordan): add first linearization lemmas for IsCommJordan	[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/) AI assistance disclosure: I used AI assistance for CI/debugging and module-structure fixes in this PR. The mathematical content and main lemmas were written by me, with help from @pelicanhere. This PR adds a new file `Mathlib/Algebra/Jordan/Linearization.lean` containing linearization lemmas for the commutative Jordan identity. Main declarations: * `IsCommJordan.four_nsmul_associator_mul_add` * `IsCommJordan.associator_mul_add` These lemmas formalize a first linearization of the commutative Jordan identity using `associator`, following McCrimmon, Proposition 1.8.5. --- I put these lemmas in a separate file because I expect follow-up linearization lemmas to belong naturally in the same place. I am also happy to rename declarations or move the file if reviewers would prefer.	t-algebra new-contributor awaiting-author label:t-algebra$	60/0	Mathlib.lean,Mathlib/Algebra/Jordan/Linearization.lean	2	6	['Yaohua-Leo', 'github-actions', 'grunweg', 'ocfnash']	ocfnash assignee:ocfnash	60-13500 1 month ago	60-13500 60 days ago	13-5927 13 days
36813	AlexeyMilovanov author:AlexeyMilovanov	feat(Computability.Encoding): add self-delimiting unary and pair encodings	Adds `unaryPrefix` (a self-delimiting $1^n 0$ code) and `prefixPair` to `Mathlib.Computability.Encoding`. Key changes: * `unaryPrefix`: A prefix-free unary encoding for $\mathbb{N}$, distinct from the existing `unaryEncodeNat`. * `unaryPrefix_append_inj`: A basic cancellation lemma that allows unique extraction of a unary prefix from a concatenated list. * `prefixPair`: A self-delimiting pairing function for boolean lists, defined as $\text{unaryPrefix } \|x\| \frown x \frown y$. * `prefixPair_inj`: A concise proof of pair injectivity leveraging the new prefix lemmas.	t-computability new-contributor awaiting-author	56/1	Mathlib/Computability/Encoding.lean	1	2	['Komyyy', 'github-actions']	Komyyy assignee:Komyyy	59-40921 1 month ago	59-40921 59 days ago	16-41519 16 days
37644	matthunz author:matthunz	feat(Order/Causal): add `Causal` ordering for stream functions	Adds `Causal` ordering for stream functions and related theorems: ```lean def Causal (f : Stream' α → Stream' β) : Prop := ∀ (x y : Stream' α) (t : ℕ), (∀ s, s ≤ t → x s = y s) → f x t = f y t ``` A stream function is causal if the output at time `t` depends only on inputs up to time `t`. Causal stream functions are commonly used in signal processing, reactive systems, and semantics of stateful computations, where outputs cannot depend on future inputs. ## Future work - Mealy machines: define Mealy machines as causal stream functions with state, and relate them to standard automata-theoretic constructions. - Feedback and delay operators: formalize feedback loops and delayed composition, enabling modeling of stateful and recursive stream definitions. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-order	79/0	Mathlib.lean,Mathlib/Order/Causal/Basic.lean,Mathlib/Order/Causal/Defs.lean	3	2	['github-actions']	nobody	58-66384 1 month ago	unknown	unknown
37695	Morten-Ness author:Morten-Ness	refactor(GroupTheory/Complement): simplify complement proofs	Simplifies the proofs of: - `Subgroup.IsComplement'.symm` - `Subgroup.isComplement_singleton_left` - `Subgroup.isComplement_singleton_right` No API changes. AI assistance: I used Codex/LLM suggestions as a starting point, then manually checked the proofs, and verified the final version locally. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-group-theory new-contributor awaiting-author	15/17	Mathlib/GroupTheory/Complement.lean	1	4	['github-actions', 'tb65536']	tb65536 assignee:tb65536	56-21674 1 month ago	56-21674 56 days ago	0-66893 18 hours
37489	michael-novak-math author:michael-novak-math	feat: add the fundamental theorem of plane curves	We add to the PlaneCurves file created in PR #36731 a classical result in the subject of differential geometry of plane curves: the fundamental theorem of plane curves. --------- - [ ] depends on: #36731	new-contributor t-differential-geometry t-analysis blocked-by-other-PR	651/0	Mathlib.lean,Mathlib/Analysis/InnerProductSpace/Calculus.lean,Mathlib/Geometry/PlaneCurves.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/FundThmCalculus.lean,docs/references.bib	5	5	['github-actions', 'mathlib-dependent-issues', 'michael-novak-math']	nobody	56-12254 1 month ago	61-83510 61 days ago	0-11137 3 hours
37281	AltSoKoly author:AltSoKoly	Update EdgeConnectivity.lean	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor awaiting-author	123/0	Mathlib/Combinatorics/SimpleGraph/Connectivity/EdgeConnectivity.lean,Mathlib/Data/Int/GCD.lean	2	5	['github-actions', 'grunweg', 'themathqueen']	nobody	55-865 1 month ago	unknown	unknown
37111	tannerduve author:tannerduve	feat(Computability): add Nat.PrimrecIn and PrimrecIn	- Add `Nat.PrimrecIn`: primitive recursive functions relative to a set of oracles - Add `PrimrecIn`: lifts `Nat.PrimrecIn` to `Primcodable` types A `PrimrecIn` version of `RecursiveIn.iff_nat` (i.e., `PrimrecIn O (f : ℕ → ℕ) ↔ Nat.PrimrecIn O f`) is left as future work as it requires proving `Nat.PrimrecIn O Nat.pred`, which needs additional API for `Nat.PrimrecIn`. --- Split out from #34937 as requested in review. - [x] depends on: #37061	t-computability new-contributor awaiting-author	24/0	Mathlib/Computability/RecursiveIn.lean	1	14	['Komyyy', 'bryangingechen', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'tannerduve']	nobody	52-65778 1 month ago	53-78637 53 days ago	1-77226 1 day
37954	jdhart81 author:jdhart81	feat(Data/ENNReal/Inv): add ENNReal.div_mul_div_cancel	Proves a / b * (b / c) = a / c for b ≠ 0, b ≠ ∞ in ENNReal. Proof via mul_div_assoc and existing div_mul_cancel. AI Disclosure: This PR was developed with assistance from an LLM (Claude, Anthropic) for proof exploration and text drafting. The proof was compiled and verified locally by the contributor, who understands the mathematical content. This lemma is extracted from a larger formalization of information-theoretic bounds (Zenodo DOI: 10.5281/zenodo.19317983). --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor	5/0	Mathlib/Data/ENNReal/Inv.lean	1	2	['github-actions']	nobody	51-2237 1 month ago	unknown	unknown
36770	Xmask19 author:Xmask19	feat: invariance of domain via Brouwer's fixed point theorem	Continuous and injective maps from Rn to Rn are open mappings. This is shown given Brouwer's fixed point theorem. The specific version of Brouwer's theorem assumed is that a continuous map from the closed unit ball to itself has a fixed point. It is used to show a lemma in this proof. Then assuming that invariance of domain isn't true gives a contradiction with this lemma. --- My supervisor has code for studying topological manifolds which relies on invariance of domain that can be found here: https://github.com/stevensivek/TopologicalManifolds and is planned to be submitted to Mathlib. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor	617/5	Mathlib.lean,Mathlib/AlgebraicTopology/InvarianceOfDomain.lean,Mathlib/Analysis/Convex/GaugeRescale.lean,Mathlib/Topology/Closure.lean,Mathlib/Topology/Order.lean	5	2	['github-actions']	nobody	47-72899 1 month ago	unknown	unknown
38050	WilliamCoram author:WilliamCoram	feat: Define Newton polygons	In this file we construct a method to define newton polygons using a Stream' of `Step`'s which correspond to what you would obtain via the 'algorithm' of rotating half-planes as described in Gouvea's p-adic numbers. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor	620/0	Mathlib.lean,Mathlib/NumberTheory/NewtonPolygon.lean	2	3	['github-actions', 'jcommelin']	nobody	47-62945 1 month ago	unknown	unknown
38113	robo7179 author:robo7179	feat(SimpleGraph/PerfectGraph): add lemma graph is perfect iff all su…	Perfect graph theorem , discussion on zulip thread: [#graph theory > Second Order Monadic Logic](https://leanprover.zulipchat.com/#narrow/channel/252551-graph-theory/topic/Second.20Order.20Monadic.20Logic.20for.20Graph/with/583013775) - [ ] depends on: #37680 - [ ] depends on: #37598	t-combinatorics new-contributor blocked-by-other-PR	54/0	Mathlib/Combinatorics/SimpleGraph/PerfectGraph.lean	1	3	['github-actions', 'mathlib-dependent-issues']	nobody	47-11264 1 month ago	unknown	unknown
37938	SamuelSchlesinger author:SamuelSchlesinger	feat(Probability/Posterior): Posterior PMFs and Various Lemmas	Upstreaming the probability lemmas needed in https://github.com/leanprover/cslib/pull/464.	t-measure-probability new-contributor awaiting-author	130/0	Mathlib.lean,Mathlib/Probability/ProbabilityMassFunction/Posterior.lean	2	6	['EtienneC30', 'SamuelSchlesinger', 'github-actions']	RemyDegenne assignee:RemyDegenne	46-59007 1 month ago	48-6051 48 days ago	0-2330 38 minutes
38139	sidbedi author:sidbedi	chore(Algebra/MvPolynomial/Variables): golf MvPolynomial.vars_0 to rfl	--- The classical qualifier and explicit rewrite chain are unnecessary — the result holds definitionally. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-algebra awaiting-author label:t-algebra$	1/2	Mathlib/Algebra/MvPolynomial/Variables.lean	1	3	['github-actions', 'grunweg']	nobody	46-17067 1 month ago	46-17067 46 days ago	0-32811 9 hours
38140	sidbedi author:sidbedi	chore(Data/Analysis/Filter): golf CFilter.ofEquiv_val to rfl	--- cases F is unnecessary, the result holds definitionally. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor awaiting-author	1/2	Mathlib/Data/Analysis/Filter.lean	1	3	['github-actions', 'grunweg']	nobody	46-17023 1 month ago	46-17023 46 days ago	0-33717 9 hours
36731	michael-novak-math author:michael-novak-math	feat: Frénet moving frame and Frénet equation for plane curves	We define the curvature function, normal vector function and the Frénet moving frame for plane curve. We also prove the Frénet equations for plane curves. A separate PR (#37489) will prove the fundamental theorem of plane curves.	new-contributor t-differential-geometry t-analysis awaiting-author	321/0	Mathlib.lean,Mathlib/Analysis/InnerProductSpace/Calculus.lean,Mathlib/Geometry/PlaneCurves.lean,Mathlib/MeasureTheory/Integral/IntervalIntegral/FundThmCalculus.lean,docs/references.bib	5	114	['Ruben-VandeVelde', 'github-actions', 'grunweg', 'michael-novak-math', 'scholzhannah']	nobody	46-11004 1 month ago	58-75027 58 days ago	12-731 12 days
37683	SabrinaJewson author:SabrinaJewson	feat(Order/OrdContinuous): every map between complete lattices that preserves sSup is a left adjoint of some Galois connection	It is already proven that the left side of a Galois connection is left-continuous; this provides the converse. --- - [ ] depends on: #37682 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor blocked-by-other-PR merge-conflict t-order	90/136	Mathlib/Order/ConditionallyCompleteLattice/Basic.lean,Mathlib/Order/ConditionallyCompletePartialOrder/Defs.lean,Mathlib/Order/OrdContinuous.lean,Mathlib/Order/SemiconjSup.lean,Mathlib/Tactic/Translate/ToDual.lean,Mathlib/Topology/Order/Basic.lean	6	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	45-78031 1 month ago	unknown	unknown
37684	SabrinaJewson author:SabrinaJewson	feat(Topology/Order): provide lemmas linking topological continuity to order continuity	All the hard work is already done, but this just fills in a couple convenient missing pieces. --- - [ ] depends on: #37682 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor blocked-by-other-PR merge-conflict t-topology	106/136	Mathlib/Order/ConditionallyCompleteLattice/Basic.lean,Mathlib/Order/ConditionallyCompletePartialOrder/Defs.lean,Mathlib/Order/OrdContinuous.lean,Mathlib/Order/SemiconjSup.lean,Mathlib/Tactic/Translate/ToDual.lean,Mathlib/Topology/Order/Basic.lean,Mathlib/Topology/Order/IsLUB.lean,Mathlib/Topology/Order/Monotone.lean	8	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	45-78020 1 month ago	unknown	unknown
37376	NoneMore author:NoneMore	feat(Topology/CantorBendixson): add iterated derived sets and perfect kernel	Define the transfinite iteration of the relative derived-set operator via `gfpApprox` and introduce the perfect kernel of a set. --- AI disclosure: Most declarations, comments, and documentation in this PR were generated with Codex. Some proofs were structurally simplified using the `/golf` command from Lean 4 Skills. I reviewed the resulting code and documentation and can vouch for all submitted content. - [ ] depends on: #37374 - [x] depends on: #37375 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor blocked-by-other-PR t-topology	249/0	Mathlib.lean,Mathlib/SetTheory/Ordinal/FixedPointApproximants.lean,Mathlib/Topology/CantorBendixson.lean,Mathlib/Topology/DerivedSet.lean	4	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	45-77989 1 month ago	unknown	unknown
38154	ybenmeur author:ybenmeur	add subsingleton case to ExpChar	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor label:t-algebra$	113/49	Mathlib/Algebra/CharP/Algebra.lean,Mathlib/Algebra/CharP/Basic.lean,Mathlib/Algebra/CharP/Defs.lean,Mathlib/Algebra/CharP/Lemmas.lean,Mathlib/Algebra/CharP/Subring.lean,Mathlib/Algebra/Polynomial/Expand.lean,Mathlib/FieldTheory/Perfect.lean,Mathlib/FieldTheory/PurelyInseparable/Exponent.lean,Mathlib/FieldTheory/SeparableDegree.lean,Mathlib/FieldTheory/SeparablyGenerated.lean,Mathlib/RingTheory/MvPolynomial/Basic.lean,Mathlib/RingTheory/MvPowerSeries/Expand.lean,Mathlib/RingTheory/Polynomial/Basic.lean,Mathlib/RingTheory/Polynomial/SeparableDegree.lean,Mathlib/RingTheory/Trace/Basic.lean	15	2	['github-actions']	nobody	44-85789 1 month ago	unknown	unknown
37593	IlPreteRosso author:IlPreteRosso	refactor(Data.Finset.Antidiagonal): rename set-based defs to `setAntidiagonal`	Renames set-based `Finset.mulAntidiagonal` → `setMulAntidiagonal` (and SMul/VAdd variants) to free the `mulAntidiagonal` name for the planned `HasMulAntidiagonal` typeclass. Deprecation aliases added. Supersedes #34551	t-ring-theory new-contributor merge-conflict	178/96	Mathlib/Algebra/Order/Antidiag/Prod.lean,Mathlib/Data/Finset/MulAntidiagonal.lean,Mathlib/Data/Finset/SMulAntidiagonal.lean,Mathlib/RingTheory/HahnSeries/Multiplication.lean,Mathlib/RingTheory/HahnSeries/PowerSeries.lean,Mathlib/RingTheory/HahnSeries/Summable.lean	6	3	['github-actions', 'mathlib-merge-conflicts']	nobody	44-29416 1 month ago	44-29417 44 days ago	15-58995 15 days
38270	Deicyde author:Deicyde	feat(Geometry/Manifold): The Tangent Functor on `MfldCat`	A simple motivating example for PR #38223. We define the `tangentFunctor : MfldCat 𝕜 (n + 1) ⥤ MfldCat 𝕜 n` which takes any manifold to its tangent bundle and any smooth map to its pushforward. This is a standard construction in differential geometry. See: J. Lee, Smooth Manifolds, pg. 75 --- - [ ] depends on: #38223 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-differential-geometry blocked-by-other-PR new-contributor	320/0	Mathlib.lean,Mathlib/Geometry/Manifold/Category/MfldCat/Basic.lean,Mathlib/Geometry/Manifold/Category/MfldCat/TangentFunctor.lean,Mathlib/Geometry/Manifold/ContMDiffMap.lean	4	3	['github-actions', 'mathlib-dependent-issues']	nobody	43-42472 1 month ago	unknown	unknown
38053	ntapiam author:ntapiam	feat(Analysis/Controls): add Control functions	Add Control functions ---- This PR adds Control functions in the sense of rough paths theory (see e.g. [Friz-Victoir, Section 1.2.1](https://page.math.tu-berlin.de/~friz/master4_May6th.pdf)). They are related to p-variation norms which are the goal of #38055. I've shown most results in the above reference though those relating to 1-variation are still a work in progress. I had to add a few statements about convex functions in order to work over NNReal instead or Real, but I am not sure this is the best way to do it. The reason is that I've defined controls as taking values in NNReal (as they should). In particular there is ```lean4 theorem nnreal_of_real {f : ℝ≥0 → ℝ≥0} (hf : ConvexOn ℝ (Set.Ici 0) fun x : ℝ => (f x.toNNReal : ℝ)) : ConvexOn ℝ≥0 ⊤ f ``` which I didn't know where to put. It probably holds in more generality but I didn't check. I have also included two versions of Controls, one global and one restricted to a set. I tried to follow Mathlib conventions as best as I could but perhaps that could be improved as well. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-analysis new-contributor	571/1	Mathlib.lean,Mathlib/Analysis/Controls/BoundedVariation.lean,Mathlib/Analysis/Controls/ControlOn.lean,Mathlib/Analysis/Controls/Defs.lean,Mathlib/Analysis/Convex/Function.lean,docs/references.bib	6	4	['github-actions', 'ntapiam']	nobody	43-11520 1 month ago	unknown	unknown
38399	openendings author:openendings	feat: OrderHom.instOrderSupSet for LawfulSup	Currently we have `instance [CompleteLattice β] : SupSet (α →o β)`. We replace this with a mere `LawfulSup` assumption such as #38328, . TODO: - [ ] construct an `OrderSupSet` instance instead of `SupSet` --- WIP - [ ] depends on: #38328 [or other `LawfulSup`] (based on master in case something else needs this) [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP t-order new-contributor blocked-by-other-PR	26/0	Mathlib/Order/Hom/Order.lean	1	5	['github-actions', 'mathlib-bors', 'mathlib-dependent-issues', 'openendings']	nobody	40-31372 1 month ago	unknown	unknown
38388	supermanG author:supermanG	feat(Combinatorics/SimpleGraph): add ballFinset with basic identities	Introduces `SimpleGraph.ballFinset`, the `Finset` companion to `SimpleGraph.ball` (#36443) on graphs with a `Fintype` vertex set, together with the basic identities `mem_ballFinset`, `ballFinset_zero`, and `ballFinset_one`. `SimpleGraph.ball` is the open metric ball `{u \| edist u c < r}` and is indexed by `ℕ∞`; `ballFinset` is typed `ℕ → Finset V` for ergonomics at cardinality-facing call sites. The classical closed-ball cardinality at radius `r`, `\|{u \| edist u c ≤ r}\|`, corresponds to `\|ballFinset v (r + 1)\|` in this setup. Opened as draft so CI can run before pinging maintainers. --- First-time Mathlib contribution — happy to adjust naming, file placement, or docstring style to match house conventions. Follow-up PRs will add cardinality envelopes (sphere cardinality, geometric-series bound, polynomial bound).	t-combinatorics new-contributor LLM-generated	68/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/BallCardinality.lean	2	3	['SnirBroshi', 'github-actions']	nobody	39-83822 1 month ago	unknown	unknown
36853	matthunz author:matthunz	feat(CategoryTheory/Monoidal/Braded/Traced): add `TracedCategory` class	Adds a `TracedCategory` class following [A. Joyal and R. Street and D. R. Verity, Traced monoidal categories](https://www.cambridge.org/core/journals/mathematical-proceedings-of-the-cambridge-philosophical-society/article/abs/traced-monoidal-categories/2BE85628D269D9FABAB41B6364E117C8#article): ```lean /-- A traced symmetric monoidal category. -/ class TracedCategory (C : Type u) [Category.{v} C] [MonoidalCategory.{v} C] [SymmetricCategory.{v} C] where /-- The trace operator. -/ trace : ∀ {A B : C} (W : C), (A ⊗ W ⟶ B ⊗ W) → (A ⟶ B) /-- Left tightening: sliding a morphism past the trace on the left. -/ trace_naturality_left : ∀ {A A' B : C} (W : C) (f : A' ⟶ A) (g : A ⊗ W ⟶ B ⊗ W), trace W (f ▷ W ≫ g) = f ≫ trace W g := by cat_disch /-- Right tightening: sliding a morphism past the trace on the right. -/ trace_naturality_right : ∀ {A B B' : C} (W : C) (f : A ⊗ W ⟶ B ⊗ W) (g : B ⟶ B'), trace W (f ≫ g ▷ W) = trace W f ≫ g := by cat_disch /-- Sliding: an endomorphism on the feedback wire slides past the trace. -/ trace_dinaturality : ∀ {A B W : C} (f : A ⊗ W ⟶ B ⊗ W) (h : W ⟶ W), trace W (f ≫ B ◁ h) = trace W (A ◁ h ≫ f) := by cat_disch /-- Superposing: trace commutes with left tensoring by a bystander object. -/ trace_superposing : ∀ {A B : C} (C' W : C) (f : A ⊗ W ⟶ B ⊗ W), C' ◁ trace W f = trace W ((α_ C' A W).hom ≫ C' ◁ f ≫ (α_ C' B W).inv) := by cat_disch /-- Vanishing I: trace over the tensor unit is the morphism itself (up to unitors). -/ trace_vanishing_one : ∀ {A B : C} (f : A ⊗ 𝟙_ C ⟶ B ⊗ 𝟙_ C), trace (𝟙_ C) f = (ρ_ A).inv ≫ f ≫ (ρ_ B).hom := by cat_disch /-- Vanishing II: trace over a tensor product equals iterated trace. -/ trace_vanishing_two : ∀ {A B X Y : C} (f : A ⊗ (X ⊗ Y) ⟶ B ⊗ (X ⊗ Y)), trace (X ⊗ Y) f = trace X (trace Y ((α_ A X Y).hom ≫ f ≫ (α_ B X Y).inv)) := by cat_disch /-- Yanking: the trace of the braiding is the identity. -/ trace_yanking : ∀ (W : C), trace W (β_ W W).hom = 𝟙 W := by cat_disch ``` ## Motivation `TracedCategory` can be used for denoting things like electric circuits, which require a traced symmetric monoidal category for the wire graph network. ## Future work - `instance [CompactClosedCategory C] : TracedCategory C` - possible notation such as `Tr_[W] f` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-category-theory new-contributor awaiting-author merge-conflict	237/0	Mathlib.lean,Mathlib/CategoryTheory/Monoidal/Braided/Traced.lean,Mathlib/CategoryTheory/Monoidal/Rigid/Traced.lean,docs/references.bib	4	5	['dagurtomas', 'github-actions', 'mathlib-merge-conflicts', 'matthunz']	nobody	38-77921 1 month ago	74-67484 74 days ago	0-24596 6 hours
38344	robo7179 author:robo7179	feat(SimpleGraph/Coloring/VertexColoring): Matching is 2 colorable	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	51/0	Mathlib/Combinatorics/SimpleGraph/Coloring/VertexColoring.lean	1	5	['SnirBroshi', 'github-actions', 'vlad902']	nobody	38-13784 1 month ago	41-67006 41 days ago	41-66756 41 days
38546	yhx-12243 author:yhx-12243	fix: universe issue in injective module	Change the definition of ```lean class Module.Injective : Prop where out : ∀ ⦃X Y : Type v⦄ [AddCommGroup X] [AddCommGroup Y] [Module R X] [Module R Y] (f : X →ₗ[R] Y) (_ : Function.Injective f) (g : X →ₗ[R] Q), ∃ h : Y →ₗ[R] Q, ∀ x, h (f x) = g x ``` into ```lean class Module.Injective : Prop where out : ∀ ⦃X Y : Type u⦄ [AddCommGroup X] [AddCommGroup Y] [Module R X] [Module R Y] (f : X →ₗ[R] Y) (_ : Function.Injective f) (g : X →ₗ[R] Q), ∃ h : Y →ₗ[R] Q, ∀ x, h (f x) = g x ``` to make it agree with `Module.Baer` and real mathematical definition, without universe issues. Since the criterion `Module.Flat` also uses `Type u` on testing modules. See discussions in https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Universe.20issue.20about.20injective.20module . --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-zulip label:t-algebra$	57/43	Mathlib/Algebra/Category/ModuleCat/Injective.lean,Mathlib/Algebra/Category/ModuleCat/Ulift.lean,Mathlib/Algebra/Module/Injective.lean,Mathlib/RepresentationTheory/FinGroupCharZero.lean,Mathlib/RingTheory/Flat/Tensor.lean,Mathlib/RingTheory/LocalProperties/Injective.lean	6	5	['github-actions', 'grunweg', 'mathlib-bors', 'wwylele']	nobody	36-64619 1 month ago	36-64630 36 days ago	0-24433 6 hours
36850	whocares-abt author:whocares-abt	feat(Combinatorics/SimpleGraph/Acyclic): deleting leaves from a tree gives a tree	Added theorem stating Deleting a leaf from a tree produces a tree.	t-combinatorics new-contributor awaiting-author	5/0	Mathlib/Combinatorics/SimpleGraph/Acyclic.lean	1	9	['YaelDillies', 'github-actions', 'vlad902']	YaelDillies assignee:YaelDillies	36-22799 1 month ago	36-22909 36 days ago	38-71219 38 days
37774	weisbrja author:weisbrja	fix: change variables in `bicompl` to `Sort*` and add missing theorem mentioned in `bicompl` docs	[#mathlib4 > Why does Mathlib use Type* instead of Sort* in some places?](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Why.20does.20Mathlib.20use.20Type.2A.20instead.20of.20Sort.2A.20in.20some.20places.3F/with/583882342) --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-logic merge-conflict	6/1	Mathlib/Logic/Function/Basic.lean	1	8	['github-actions', 'kbuzzard', 'leanprover-radar', 'mathlib-merge-conflicts', 'weisbrja']	nobody	35-72326 1 month ago	35-72327 35 days ago	19-66334 19 days
37445	edwin1729 author:edwin1729	feat(Topology/Order): set of compact elements, generating basic opens contained in a `Locale.PT`, is directed	This is (2/4) PRs culminating in a proof that "Scott Topologies over Algebraic DCPOs are Sober". In this PR we prove properties of a certain set of compact elements, w.r.t a `Locale.PT`. A `Locale.PT` can be thought of as a set of `Opens`. Precisely it is a Frame homomorphism from `Opens _` to `Prop` so we are essentially choosing certain `Opens` to form our set and this set has additional properties. Namely it is a completely prime filter: if the supremum of some Opens is contained than atleast one of the Opens must be contained. Take some `Locale.PT`, `x`. In this PR, we prove that the set of compact elements generating basic opens (compact elements generate topological basis see #31662) contained in `x` is directed. This set of compact elements defined above is important in subsequent parts of the proof since it fully determines `x`. - [ ] depends on: #31662 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology blocked-by-other-PR new-contributor merge-conflict	296/1	Mathlib.lean,Mathlib/Topology/Order/ScottTopology.lean,Mathlib/Topology/Order/ScottTopologyDCPO.lean,docs/references.bib	4	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	35-55248 1 month ago	unknown	unknown
37556	edwin1729 author:edwin1729	feat(Topology/Order): Locale.localePointOfSpacePoint if we have a Scott Topology from an Algebraic DCPO	(3/4) in a series of PRs proving that "Scott Topologies over Algebraic DCPOs are Sober" We prove here that the unit of the adjunction from `TopCat` to `Locale` defined in `Topology/Order/Category/FrameAdjunction.lean` is a surjective mapping, under the following condition: The underlying TopologicalSpace must be a Scott Topology generated with an underlying Algebraic DCPO structure. - [ ] depends on: #37445 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor blocked-by-other-PR merge-conflict	393/1	Mathlib.lean,Mathlib/Topology/Order/ScottTopology.lean,Mathlib/Topology/Order/ScottTopologyDCPO.lean,docs/references.bib	4	5	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	35-55247 1 month ago	60-79747 60 days ago	0-562 9 minutes
38560	Deicyde author:Deicyde	feat(Geometry/Manifold): `MfldCat` is a `CartesianMonoidalCategory`	We prove that the category `MfldCat` of C^n manifolds is a Cartesian monoidal category, and also derive the `BraidedCategory` instance. This PR introduces a new file `Geometry/Manifold/Category/MfldCat/CartesianMonoidal` closely mirroring the structure of `Algebra/Category/Grp/CartesianMonoidal.lean` --- - [ ] depends on: #38223 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-differential-geometry blocked-by-other-PR new-contributor	281/0	Mathlib.lean,Mathlib/Geometry/Manifold/Category/MfldCat/Basic.lean,Mathlib/Geometry/Manifold/Category/MfldCat/CartesianMonoidal.lean,Mathlib/Geometry/Manifold/ContMDiffMap.lean	4	3	['github-actions', 'mathlib-dependent-issues']	nobody	35-28493 1 month ago	unknown	unknown
38364	openendings author:openendings	feat: create Order/DirectedCompletePartialOrder/Defs.lean	Define DirectedCompletePartialOrder and its interaction with iSup and sSup. --- A DirectedCompletePartialOrder is equivalently: - a partial order with LUBs of nonempty directed sets; - what happens when you remove ⊥ from a CompletePartialOrder; or - a ConditionallyCompletePartialOrder in which every directed set is BddAbove. Like CPOs, DCPOs are commonly studied in denotational semantics. Potential applications: - [#Is there code for X? > Summing `ENat`s without topology](https://leanprover.zulipchat.com/#narrow/channel/217875-Is-there-code-for-X.3F/topic/Summing.20.60ENat.60s.20without.20topology/with/590070848) -- defining infinite sums in an DCPO-enriched `AddCommMonoidWithTop` such as `ENat` or `ENNReal`. - [#Is there code for X? > Scott Induction](https://leanprover.zulipchat.com/#narrow/channel/217875-Is-there-code-for-X.3F/topic/Scott.20Induction/with/590112858) -- fixpoint theorems similar to `OmegaCompletePartialOrder`, generalised to arbitrary cardinalities. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order new-contributor	123/0	Mathlib.lean,Mathlib/Order/DirectedCompletePartialOrder/Defs.lean,docs/references.bib	3	4	['SnirBroshi', 'github-actions', 'openendings']	nobody	34-58040 1 month ago	40-44746 40 days ago	41-15964 41 days
37814	sglasman author:sglasman	feat: Equivalence between HopfAlgCat R and Hopf (ModuleCat R)	This PR resolves a TODO by demonstrating an equivalence of categories between two models of the category of Hopf algebras over a commutative ring R, that of Hopf objects in the module category of R and that of types with a `HopfAlgebra R` instance. --- AI declaration: I consulted with Claude on proof strategies. The proofs were ultimately written by me.	new-contributor large-import t-category-theory WIP	214/4	Mathlib/CategoryTheory/Monoidal/Hopf_.lean,Mathlib/RingTheory/HopfAlgebra/Basic.lean	2	5	['dagurtomas', 'github-actions', 'robin-carlier', 'sglasman']	kim-em assignee:kim-em	34-33011 1 month ago	39-81874 39 days ago	14-68997 14 days
38635	Fieldnote-Echo author:Fieldnote-Echo	chore(scripts): handle simple to_additive deprecations	Closes #38550. This updates `scripts/add_deprecations.sh` so that, when a renamed declaration is near an existing `@[to_additive]` attribute, the script also emits the additive deprecation alias in the common default-name case. For example, `foo_mul -> bar_mul` now produces: ```lean @[deprecated (since := "...")] alias foo_add := bar_add @[to_additive existing, deprecated (since := "...")] alias foo_mul := bar_mul ``` This is intentionally conservative and text-based, matching the existing script. It handles common name translations such as mul/add, prod/sum, one/zero, inv/neg, and div/sub, and skips cases that look like they need less common to_additive name generation. Tested with a local six-case fixture and a scratch Lean file confirming that the generated alias form compiles and produces deprecation warnings for both names. I opened this as draft because I still count as a new contributor under the LLM-assisted PR policy. I have one merged mathlib PR (#36443), and this is a one-file script patch that I reviewed/tested manually. I'll leave it as draft unless a maintainer gives it the green light to flip ready. I used Claude assistance while drafting and testing the patch. I reviewed the final diff manually and tested the generated Lean form locally.	CI new-contributor	121/10	scripts/add_deprecations.sh	1	4	['Fieldnote-Echo', 'SnirBroshi', 'github-actions']	kim-em assignee:kim-em	33-34106 1 month ago	unknown	unknown
37819	YellPika author:YellPika	feat(Order/OmegaCompletePartialOrder): add `OmegaCompletePartialOrder` instance for `WithBot` with basic `ωScottContinuous` lemmas	This is a modification of #34093. See #34093 for details. --- - [x] depends on: #33941 - [x] depends on: #37258 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-order merge-conflict	337/10	Mathlib/Algebra/Order/Ring/WithTop.lean,Mathlib/Analysis/BoxIntegral/Box/Basic.lean,Mathlib/Order/Monotone/Basic.lean,Mathlib/Order/OmegaCompletePartialOrder.lean,Mathlib/Order/TypeTags.lean,Mathlib/Order/WithBot.lean	6	5	['Komyyy', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	Komyyy assignee:Komyyy	32-36387 1 month ago	32-36387 32 days ago	22-4315 22 days
38056	Deicyde author:Deicyde	feat: topological vector bundle homomorphisms	This PR implements topological vector bundle morphisms. - [ ] depends on: #38023 - [ ] depends on: #37946 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-topology merge-conflict	805/0	Mathlib/Analysis/Normed/Module/FiniteDimension.lean,Mathlib/Topology/FiberBundle/Basic.lean,Mathlib/Topology/FiberBundle/Trivialization.lean,Mathlib/Topology/VectorBundle/Basic.lean,Mathlib/Topology/VectorBundle/Morphism.lean	5	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	31-68632 1 month ago	unknown	unknown
38316	tannerduve author:tannerduve	feat(Order/OmegaCompletePartialOrder): least fixed point and Scott induction	Adds `ContinuousHom.lfp` for endomorphisms on an ωCPO with `⊥`, as the `ωSup` of the iterate chain from `⊥`, together with `map_lfp`, `isFixedPt_lfp`, `lfp_le_fixed`, `isLeast_lfp`, and the Scott induction theorem `lfp_induction` (specialized from a more general seed-based `ωSup_iterate_induction`). For `Part.fix`, adds: * `Part.exists_mem_approx_of_mem_fix`: if `y ∈ Part.fix g x`, some finite approximation of `g` already contains `y`. * `Part.Fix.approx_eq_iterate_bot` and `Part.Fix.approxChain_eq_iterateChain`: bridges between `Fix.approx`/`approxChain` and `f^[n] ⊥`/`iterateChain`. * `Part.fix_eq_lfp`: `Part.fix g = ContinuousHom.lfp (.ofFun g hc)` when `g` is ω-Scott continuous. * `Part.fix_scott_induction`: Scott induction specialized to `Part.fix`. * `Part.fix_induction_mem`: membership induction on `Part.fix`, derived from `fix_scott_induction`.	new-contributor	114/0	Mathlib/Control/LawfulFix.lean,Mathlib/Order/OmegaCompletePartialOrder.lean,docs/references.bib	3	2	['github-actions']	nobody	30-74520 30 days ago	30-73823 30 days ago	42-43117 42 days
38871	0xTerencePrime author:0xTerencePrime	feat(Combinatorics/SimpleGraph): add parity lemmas for outer and inner vertices	Adds three lemmas to `SimpleGraph.DegreeSum`: - `sum_degrees_option_zmod_two`: the handshaking lemma for `Option I` over ZMod 2 - `degree_none_zmod_two_eq_sum`: simp-normal form of the above - `card_degree_one_option_eq_outer_zmod_two`: under degree bound ≤ 2, count of degree-1 inner vertices equals outer vertex degree mod 2	t-combinatorics new-contributor	65/3	Mathlib/Combinatorics/SimpleGraph/DegreeSum.lean	1	6	['0xTerencePrime', 'SnirBroshi', 'github-actions']	nobody	29-37605 29 days ago	29-43551 29 days ago	30-4843 30 days
38897	0xTerencePrime author:0xTerencePrime	feat(Combinatorics/SetFamily): formalize 1D Sperner's Lemma parity	Formalizes the 1-dimensional Sperner's Lemma (parity version): given a coloring of the `n + 1` vertices of a subdivided line segment with two colors (`ZMod 2`), if the two endpoints have different colors, then the number of color-changing edges is odd. This is distinct from `IsAntichain.sperner` in `SetFamily.LYM`, which concerns antichains in a power set. This file formalizes the topological/combinatorial parity statement used as the base case in higher-dimensional Sperner arguments. ## Key declarations - `SpernerColoring`: type-safe coloring via `Fin (n + 1) → ZMod 2` - `edgeDiff`: color difference on adjacent vertices, computed in `ZMod 2` - `totalDiff`: telescoping sum of all edge differences - `diffEdges`: the `Finset` of bichromatic (color-changing) edges - `sperner_1d`: main theorem — `Odd (diffEdges c).card` ## Design notes - Using `Fin (n + 1) → ZMod 2` instead of `ℕ → ZMod 2` makes boundary conditions unrepresentable at the type level, eliminating out-of-bounds cases entirely. - The proof reduces to a telescoping sum in `ZMod 2`, using `CharTwo.add_self_eq_zero` to cancel all interior vertices, avoiding parity case splits. This is intended as the 1D base case, the approach generalizes to higher-dimensional Sperner's Lemma in future work. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	133/0	Mathlib.lean,Mathlib/Combinatorics/SetFamily/Sperner1D.lean	2	3	['github-actions', 'grunweg']	nobody	29-28839 29 days ago	29-38259 29 days ago	29-38009 29 days
38750	openendings author:openendings	feat(Data/Nat): add padicValNat_add_eq_min	Add lemmas for `padicValNat` mirroring the [e]multiplicity API, including - padicValNat_eq_of_dvd_of_not_dvd - padicValNat_add_of_gt - padicValNat_add_eq_min --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor awaiting-author	36/0	Mathlib/Data/Nat/MaxPowDiv.lean	1	7	['Ruben-VandeVelde', 'github-actions', 'openendings']	nobody	29-25864 29 days ago	29-51360 29 days ago	3-59736 3 days
38170	maddycrim author:maddycrim	feat(Algebra/Module/FinitePresentation): Finitely Presented Module Lemma	From FLT Project Main Definitions: `Module.FinitePresentation.exists_fin_exact` : A finitely presented module M admits an exact sequence F' -> F -> M -> 0 where F' and F are finite free modules. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author label:t-algebra$	9/0	Mathlib/Algebra/Module/FinitePresentation.lean	1	17	['chrisflav', 'github-actions', 'maddycrim', 'themathqueen', 'vlad902']	nobody	28-24195 28 days ago	28-24195 28 days ago	17-35026 17 days
38951	thomaskwaring author:thomaskwaring	feat(Order/PrimeSeparator): remove unnecessary hypotheses	In `mem_ideal_sup_principal`, boundedness and distributivity were unused, and in `prime_ideal_of_disjoint_filter_ideal`, boundedness was only used to produce an element of the filter `F`, which is already nonempty by definition. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order new-contributor	9/19	Mathlib/Order/PrimeSeparator.lean	1	2	['github-actions']	nobody	28-21530 28 days ago	28-20870 28 days ago	28-20620 28 days
36896	PieterCuijpers author:PieterCuijpers	feat (Algebra/Order/Quantale): isMulLeftsided, isMulRightsided, isMulTwosided and strict versions	* Adding definitions of quantale elements being leftsided, rightsided, and twosided, and strict versions Should we include these definitions in the main Algebra/Order/Quantale.lean file, or start a separate file for them? I have a few basic theorems I would like to include on these notions, but invite suggestions. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author label:t-algebra$	81/1	Mathlib/Algebra/Order/Quantale.lean	1	5	['NoahW314', 'PieterCuijpers', 'chrisflav', 'github-actions']	mariainesdff assignee:mariainesdff	28-5340 28 days ago	34-83995 34 days ago	39-15412 39 days
38973	hyeoniuwu author:hyeoniuwu	feat(Computability): define (single oracle) turing reducibility, relate it to RecursiveIn and prove basic jump theorems	feat(Computability): define (single oracle) Turing reducibility, relate it to RecursiveIn and prove basic jump theorems Defines Turing reducibility and the jump operator, with total functions (from naturals to naturals) as oracles. Defines codes for basic primitive recursive functions, and the evaluation function. Proves basic reducibility arguments, such as `K0_eq_K` asserting that K0 of an oracle is Turing equivalent to K of an oracle. Our reducibility is related back to `RecursiveIn` as is currently defined in Mathlib via the theorem `SingleReducibleIff`. This is part of a larger repository where more advanced theorems such as KP54 have been proven. (https://github.com/hyeoniuwu/CiL) Co-authored-by: Tanner Duve --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor awaiting-author	4988/0	Mathlib/Computability/SingleOracle/Basic.lean,Mathlib/Computability/SingleOracle/Constructions/Basic.lean,Mathlib/Computability/SingleOracle/Constructions/CovRec.lean,Mathlib/Computability/SingleOracle/Constructions/Dovetail.lean,Mathlib/Computability/SingleOracle/Constructions/Eval.lean,Mathlib/Computability/SingleOracle/Constructions/Eval_Aux.lean,Mathlib/Computability/SingleOracle/Constructions/List.lean,Mathlib/Computability/SingleOracle/Constructions/Meta.lean,Mathlib/Computability/SingleOracle/Constructions/Option.lean,Mathlib/Computability/SingleOracle/Constructions/Primitive.lean,Mathlib/Computability/SingleOracle/Encoding.lean,Mathlib/Computability/SingleOracle/Jump.lean,Mathlib/Computability/SingleOracle/Oracle.lean,Mathlib/Computability/SingleOracle/Order.lean,Mathlib/Computability/SingleOracle/RecursiveIn.lean,Mathlib/Computability/SingleOracle/Reducibilities.lean,Mathlib/Data/Option/Basic.lean,Mathlib/Tactic/Attr/Register.lean,Mathlib/Tactic/Computability/Basic.lean	19	3	['github-actions', 'grunweg']	nobody	27-63072 27 days ago	unknown	unknown
37456	Robertboy18 author:Robertboy18	feat(LinearAlgebra/AffineSpace): add parallel form of Desargues's theorem	This PR adds an affine parallel form of Desargues's theorem, corresponding to entry `87` of the Lean community “100 theorems” list and following the related Rocq/Coq affine-geometry statement. Main changes - New file `Mathlib/LinearAlgebra/AffineSpace/Desargues.lean` with `parallel_third_side_of_perspective`. - Add the corresponding `public import` to `Mathlib.lean`. - Update `docs/100.yaml` entry `87` with a note that this is the parallel affine form. Proof idea The proof compares side vectors using `exists_eq_smul_of_parallel` for the two given pairs of parallel sides. The shared comparison along `SA` forces the same scalar, which gives parallelism of the third pair of sides. Tests: `lake build Mathlib.LinearAlgebra.AffineSpace.Desargues` AI disclosure: GPT-5.2 Pro was used for assistance with web search/background details about the theorem and for finding useful existing Mathlib lemmas. The theorem statement and Lean formalization were written and checked by hand. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor awaiting-author LLM-generated label:t-algebra$	133/0	Mathlib.lean,Mathlib/LinearAlgebra/AffineSpace/Desargues.lean	2	17	['Robertboy18', 'SnirBroshi', 'copilot-pull-request-reviewer', 'eric-wieser', 'github-actions', 'wwylele']	eric-wieser assignee:eric-wieser	27-59710 27 days ago	54-1458 54 days ago	8-70344 8 days
38792	openendings author:openendings	wip, chore: rename Directed -> Predirected [please-adopt]	This incomplete PR renames `Directed` to `Predirected`. As [discussed in Zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/.3E.20complete.20partial.20order.20and.20domain.20theory.20formalization/near/592156927), `Directed` misleadingly mismatches the literature. (The literature says a directed set is nonempty, and we do not.) #### f19d3e79 Rename Directed -> Predirected (class + namespace) Automated changes: - LSP code action renaming `Directed` to `Predirected` - with the affected 69 files open in [lean.nvim](https://github.com/julian/lean.nvim), a series of commands roughly equivalent to ```nvim :bufdo :silent %s/$theorem \\|lemma \\|to_dual $Directed\>/\1Predirected/ge :bufdo :silent %s/\\./Predirected./ge :bufdo :w ``` EDIT: manual changes - one `namespace Directed` replaced. ### Corners cut: - line-length linting has not been resolved. - no snake-cased `directed` has been renamed. - only tested via `lake build --old`, plus maybe ten minutes of `lake build` before I (@openendings ) got bored and wanted my CPU back. --- WIP please-adopt t-order [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	please-adopt new-contributor WIP merge-conflict	196/195	Mathlib/Algebra/Algebra/NonUnitalSubalgebra.lean,Mathlib/Algebra/Algebra/Subalgebra/Directed.lean,Mathlib/Algebra/Field/Subfield/Basic.lean,Mathlib/Algebra/Group/Subgroup/Lattice.lean,Mathlib/Algebra/Group/Submonoid/Membership.lean,Mathlib/Algebra/Group/Subsemigroup/Membership.lean,Mathlib/Algebra/Ring/Subring/Basic.lean,Mathlib/Algebra/Ring/Subsemiring/Basic.lean,Mathlib/Algebra/Star/NonUnitalSubalgebra.lean,Mathlib/Analysis/Convex/Basic.lean,Mathlib/Analysis/Convex/Strict.lean,Mathlib/Analysis/InnerProductSpace/Orthonormal.lean,Mathlib/CategoryTheory/Filtered/Basic.lean,Mathlib/Data/Finset/Order.lean,Mathlib/Data/Fintype/Order.lean,Mathlib/Data/Set/Accumulate.lean,Mathlib/Data/Set/Dissipate.lean,Mathlib/Data/Set/Finite/Lattice.lean,Mathlib/Data/Set/Lattice.lean,Mathlib/Data/Set/Lattice/Image.lean,Mathlib/Data/Set/Pairwise/Lattice.lean,Mathlib/Data/Set/UnionLift.lean,Mathlib/Dynamics/PeriodicPts/Lemmas.lean,Mathlib/FieldTheory/CardinalEmb.lean,Mathlib/FieldTheory/Extension.lean,Mathlib/FieldTheory/IntermediateField/Adjoin/Basic.lean,Mathlib/LinearAlgebra/Eigenspace/Basic.lean,Mathlib/LinearAlgebra/LinearIndependent/Lemmas.lean,Mathlib/LinearAlgebra/Span/Defs.lean,Mathlib/Logic/Encodable/Basic.lean,Mathlib/MeasureTheory/Function/SimpleFunc.lean,Mathlib/MeasureTheory/Integral/Lebesgue/Add.lean,Mathlib/MeasureTheory/Integral/Lebesgue/Basic.lean,Mathlib/MeasureTheory/Integral/Lebesgue/Sub.lean,Mathlib/MeasureTheory/Measure/MeasureSpace.lean,Mathlib/MeasureTheory/Measure/Restrict.lean,Mathlib/MeasureTheory/PiSystem.lean,Mathlib/ModelTheory/Satisfiability.lean,Mathlib/ModelTheory/Substructures.lean,Mathlib/ModelTheory/Syntax.lean,Mathlib/Order/CompactlyGenerated/Basic.lean,Mathlib/Order/CompletePartialOrder.lean,Mathlib/Order/ConditionallyCompletePartialOrder/Defs.lean,Mathlib/Order/ConditionallyCompletePartialOrder/Indexed.lean,Mathlib/Order/Directed.lean,Mathlib/Order/Filter/Bases/Basic.lean,Mathlib/Order/Filter/Basic.lean,Mathlib/Order/Filter/Lift.lean,Mathlib/Order/Filter/Map.lean,Mathlib/Order/OmegaCompletePartialOrder.lean,Mathlib/Order/Preorder/Chain.lean,Mathlib/Order/RelIso/Set.lean,Mathlib/Probability/Independence/Basic.lean,Mathlib/Probability/Independence/Conditional.lean,Mathlib/Probability/Independence/Kernel/Indep.lean,Mathlib/Probability/Independence/ZeroOne.lean,Mathlib/Probability/Kernel/Disintegration/CDFToKernel.lean,Mathlib/RingTheory/AlgebraicIndependent/Basic.lean,Mathlib/RingTheory/NonUnitalSubring/Basic.lean,Mathlib/RingTheory/NonUnitalSubsemiring/Basic.lean,Mathlib/Topology/Algebra/Valued/NormedValued.lean,Mathlib/Topology/Category/TopCat/Limits/Konig.lean,Mathlib/Topology/Compactness/Compact.lean,Mathlib/Topology/Compactness/CompactSystem.lean,Mathlib/Topology/Compactness/CountablyCompact.lean,Mathlib/Topology/Semicontinuity/Basic.lean,Mathlib/Topology/Separation/Hausdorff.lean,Mathlib/Topology/Separation/Profinite.lean,Mathlib/Topology/UniformSpace/UniformConvergenceTopology.lean	69	7	['github-actions', 'kbuzzard', 'mathlib-merge-conflicts', 'openendings']	nobody	27-55099 27 days ago	unknown	unknown
38960	ajhendel author:ajhendel	chore: remove ℕ+ interval_cases workaround in ADEInequality	`interval_cases` now supports `ℕ+`, so the manual `Finset.mem_Iio`/`Finset.mem_Ico` + `conv` + `fin_cases` workaround (marked with a porting note) is no longer needed. Replaces three 3-4 line workaround blocks with `interval_cases p`/`q`/`r`.	t-number-theory new-contributor awaiting-CI	3/10	Mathlib/NumberTheory/ADEInequality.lean	1	2	['github-actions']	nobody	27-7891 27 days ago	unknown	unknown
38310	ZRTMRH author:ZRTMRH	feat(Combinatorics/Quiver/Schreier): word evaluation and reachability	Adds word evaluation and reachability results to the Schreier graph API. * `SchreierGraph.evalWord` : evaluates a word `List (S × Bool)` as an element of the ambient group, where `(s, true)` contributes `ι s` and `(s, false)` contributes `(ι s)⁻¹`. * `SchreierGraph.evalWord_eq_lift` : agreement with `FreeGroup.lift`. * `SchreierGraph.evalWord_mem_closure` : every word evaluates into the subgroup generated by `ι`. * `SchreierGraph.pathFromWord` : a Bool-tagged word yields a path in `Symmetrify (SchreierGraph V ι)` from `x` to `evalWord ι w • x`. * `SchreierGraph.reachable_iff` : two vertices are connected by a path in the symmetrification iff some element of the subgroup closure carries one to the other. Follow-up to #36320. This PR was written with AI assistance (Claude). The code has been reviewed by the author. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-combinatorics large-import LLM-generated	157/0	Mathlib/Combinatorics/Quiver/Schreier.lean	1	2	['github-actions']	nobody	26-35545 26 days ago	42-68311 42 days ago	42-68061 42 days
39023	TBUGTB author:TBUGTB	feat(Algebra/Order): API lemmas on floor and abs	Co-authored-by: Etienne Marion @EtienneC30 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra brownian new-contributor label:t-algebra$	9/0	Mathlib/Algebra/Order/Floor/Semiring.lean,Mathlib/Algebra/Order/Ring/Abs.lean	2	3	['TBUGTB', 'github-actions']	nobody	26-17271 26 days ago	26-17986 26 days ago	26-17736 26 days
38374	idontgetoutmuch author:idontgetoutmuch	Principal Bundles, Connection 1-forms and the Frame Bundle	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-differential-geometry new-contributor	2017/0	Mathlib/Geometry/Manifold/Algebra/FakeFormII.lean,Mathlib/Geometry/Manifold/Algebra/PrincipalGBundle.lean,Mathlib/Geometry/Manifold/Algebra/SmoothLieExp.lean	3	2	['github-actions']	nobody	26-6488 26 days ago	unknown	unknown
39048	AydenLamp author:AydenLamp	feat(Algebra/Group/Defs): add positive natural exponentiation for semigroups	Introduce exponentiation for semigroups with positive natural exponents. This serves as a foundation for future results on Green’s relations and Rees matrix constructions in semigroups. --- Co-authored-by: Howard Straubing Soleil Repple Nathan Hart-Hodgson [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-algebra awaiting-author label:t-algebra$	106/0	Mathlib.lean,Mathlib/Algebra/Group/SemigroupPow.lean	2	7	['ScottCarnahan', 'github-actions', 'wwylele']	nobody	25-20662 25 days ago	unknown	unknown
38476	agusakov author:agusakov	refactor(Combinatorics/Digraph): add vertex sets	--- Adopting #33466 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor awaiting-author	381/50	Mathlib/Combinatorics/Digraph/Basic.lean,Mathlib/Combinatorics/Digraph/Orientation.lean	2	16	['Shreyas4991', 'YaelDillies', 'agusakov', 'github-actions']	nobody	25-10006 25 days ago	34-28547 34 days ago	3-31839 3 days
39108	idontgetoutmuch author:idontgetoutmuch	feat(Geometry/Manifold/GroupLieAlgebra): Add mfderiv_mul_left_mul and left-translate for integral curves	Add the following: `mfderiv_mul_left_mul`: the derivative of left-multiplication satisfies a chain rule: $$d(L_{g \cdot h})_x = d(L_g)_{h \cdot x} \circ d(L_h)_x$$ `mulInvariantVectorField_mul`: the vector field at the translated point is the push forward of the vector field: $$V(g \cdot h) = d(L_g)_h(V(h))$$ `IsMIntegralCurve.left_translate`: using these, if $\gamma$ is an integral curve of $V$, then so is $t \mapsto g \bullet \gamma(t)$ for any $g \in G$, since: $$\frac{d}{dt}(g \bullet \gamma(t)) = d(L_g)_{\gamma(t)}\left(\frac{d\gamma}{dt}(t)\right) = d(L_g)_{\gamma(t)}(V(\gamma(t))) = V(g \bullet \gamma(t))$$ I argue () all the time with LLMs so this PR will certainly have had some input from them. Is that enough of a disclosure? () Like Lewis Carroll: In my youth said the sage I took to the law and argued each case with wife And the muscular strength that it gave to my jaw has lasted the rest of my life	t-differential-geometry new-contributor awaiting-author LLM-generated	73/0	Mathlib/Geometry/Manifold/GroupLieAlgebra.lean	1	8	['github-actions', 'grunweg']	nobody	23-75462 23 days ago	23-75527 23 days ago	0-37210 10 hours
39151	anovickis author:anovickis	feat(Analysis/CStarAlgebra/Matrix): IsTopologicalGroup for specialUnitaryGroup	Adds `ContinuousInv` and `IsTopologicalGroup` instances for `Matrix.specialUnitaryGroup n 𝕜`. The unitary group `Matrix.unitaryGroup n α` already inherits these via the `unitaryGroup ≡ unitary R` abbrev + existing instances on `unitary R` (in `Mathlib/Topology/Algebra/Star/Unitary.lean`). However, `specialUnitaryGroup` is the sub-Submonoid `unitaryGroup ⊓ MonoidHom.mker detMonoidHom` — it does not auto-inherit those instances since it is not literally an alias of `unitary R`. ### New declarations - `instance Matrix.specialUnitaryGroup.instContinuousInv` — proven via `Matrix.star_eq_inv` + `continuous_star` - `instance Matrix.specialUnitaryGroup.instIsTopologicalGroup` — combining `ContinuousMul` (from Submonoid structure) + `ContinuousInv` Both placed inside the existing `EntrywiseSupNorm` section in `Mathlib/Analysis/CStarAlgebra/Matrix.lean` (the natural neighborhood for matrix-specific topological structure on (special) unitary groups). ### Motivation These instances enable using `specialUnitaryGroup` as a topological group in homogeneous-space constructions (e.g., `SU(3) ⧸ T = F₂` flag manifolds). They complement #39146 (CompactSpace instances for the same groups) — together giving the standard 'compact topological group' typeclass set on `specialUnitaryGroup`. ### Verification \`\`\`lean example : ContinuousInv (Matrix.specialUnitaryGroup (Fin 3) ℂ) := inferInstance -- now works example : IsTopologicalGroup (Matrix.specialUnitaryGroup (Fin 3) ℂ) := inferInstance -- now works \`\`\` Both fail on master without this PR; both succeed after.	t-analysis new-contributor awaiting-author	30/0	Mathlib/Analysis/CStarAlgebra/Matrix.lean	1	3	['github-actions', 'j-loreaux', 'wwylele']	nobody	22-64586 22 days ago	22-64586 22 days ago	0-3025 50 minutes
39191	m13683320924-hue author:m13683320924-hue	feat: define Asymptotics.IsSubpolynomial	This PR defines `Asymptotics.IsSubpolynomial l f g`, meaning that `f` is asymptotically bounded by `1 + ‖g‖ ^ k` for some `k : ℕ`. It also adds basic closure lemmas for constants, addition, multiplication, and natural powers. Towards #32658. The formalization was developed with the help of Doubao-Seed-2.0-code and manually checked in Lean. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis new-contributor	259/0	Mathlib.lean,Mathlib/Analysis/Asymptotics/Subpolynomial.lean	2	3	['github-actions']	nobody	22-4144 22 days ago	unknown	unknown
34054	YellPika author:YellPika	feat(Order/OmegaCompletePartialOrder): OmegaCompletePartialOrder instance for `Sigma` with basic `ωScottContinuous` lemmas	This PR adds an `OmegaCompletePartialOrder` instance for `Sigma` along with `ωScottContinuous` lemmas for basic operations (`mk`, `fst`, `snd`). Appropriate lemmas are marked with `@[fun_prop]` so that the `fun_prop` tactic can automatically deduce `ωScottContinuous` proofs for functions involving `Sigma`s. --- - [x] depends on: #33941 - [x] depends on: #37258 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-order please-merge-master awaiting-author	231/0	Mathlib/Data/Sigma/Order.lean,Mathlib/Order/OmegaCompletePartialOrder.lean	2	29	['Vierkantor', 'YellPika', 'github-actions', 'grunweg', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	grunweg assignee:grunweg	21-85296 21 days ago	101-66547 101 days ago	16-56783 16 days
39213	m13683320924-hue author:m13683320924-hue	feat: define maximal cliques and independent sets	This PR adds explicit predicates for maximal cliques and maximal independent sets: - `SimpleGraph.IsMaximalClique` - `SimpleGraph.IsMaximalIndepSet` It also adds conversion lemmas to and from the existing `Maximal G.IsClique` and `Maximal G.IsIndepSet` formulations, plus basic complement and maximum-to-maximal lemmas. Towards #34962. The formalization was developed with the help of Doubao-Seed-2.0-code and manually checked in Lean. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor LLM-generated	60/22	Mathlib/Combinatorics/SimpleGraph/Clique.lean	1	3	['SnirBroshi', 'github-actions']	nobody	21-69951 21 days ago	unknown	unknown
32608	PrParadoxy author:PrParadoxy	feat(LinearAlgebra/PiTensorProduct): API for PiTensorProducts indexed by sets	This PR addresses a TODO item in LinearAlgebra/PiTensorProduct.lean: * API for the various ways ι can be split into subsets; connect this with the binary tensor product -- specifically by describing tensors of type ⨂ (i : S), M i, for S : Set ι. Our primary motivation is to formalise the notion of "restricted tensor products". This will be the content of a follow-up PR. Beyond that, the Set API is natural in contexts where the index type has an independent interpretation. An example is quantum physics, where ι ranges over distinguishable degrees of freedom, and where its is common practice to annotate objects by the set of indices they are defined on. --- Stub file with preliminary definition of the restricted tensor product as a direct limit of tensors indexed by finite subsets of an index type: https://github.com/PrParadoxy/mathlib4/blob/restricted-stub/Mathlib/LinearAlgebra/PiTensorProduct/Restricted.lean --- - [x] depends on: #32598 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor awaiting-zulip t-algebra WIP label:t-algebra$	300/2	Mathlib.lean,Mathlib/LinearAlgebra/PiTensorProduct.lean,Mathlib/LinearAlgebra/PiTensorProduct/Set.lean	3	31	['PrParadoxy', 'dagurtomas', 'eric-wieser', 'github-actions', 'goliath-klein', 'leanprover-radar', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	nobody	21-67130 21 days ago	161-77852 161 days ago	10-64694 10 days
37299	XC0R author:XC0R	feat(NumberTheory): Chebyshev's lower bound on primorial	## Summary Prove `primorial(n) ≥ 2^(n/2)` for all `n ≥ 2` (Chebyshev's 1852 lower bound). This is the lower bound complement to `primorial_le_four_pow`. Addresses the TODO at `Chebyshev.lean` line 50: "Prove Chebyshev's lower bound." ### New file: `Mathlib/NumberTheory/PrimorialLowerBound.lean` Main theorems: - `two_pow_le_primorial`: `2 ^ n ≤ primorial (2 * n)` for `n ≥ 29` - `two_pow_div_two_le_primorial`: `2 ^ (n / 2) ≤ primorial n` for `n ≥ 2` Key intermediates: - `centralBinom_le_pow_mul_primorial`: `C(2n,n) ≤ (2n)^{π(√(2n)+1)} * primorial(2n)` - `eight_mul_sq_add_le_two_pow`: `8u² + 16u + 8 ≤ 2^u` for `u ≥ 10` ### Proof technique Central binomial decomposition: from `four_pow_lt_mul_centralBinom` and `factorization_choose_le_log`, bound `C(2n,n)` above by `(2n)^{π(√(2n)+1)} * primorial(2n)`. Rearranging gives `primorial(2n) ≥ 2^n` for `n ≥ 29`. Base cases by `norm_num` + `decide`, large `n` analytically via `√n` factoring. ### AI disclosure Claude (Anthropic) was used as a coding assistant for Lean tactic exploration, file structuring, and CI debugging. All proof strategy, mathematical content, and final code have been reviewed and are understood by the author.	t-number-theory new-contributor awaiting-author	226/2	Mathlib/NumberTheory/Chebyshev.lean,Mathlib/NumberTheory/Primorial.lean	2	53	['MichaelStollBayreuth', 'Parcly-Taxel', 'XC0R', 'github-actions', 'mathlib-merge-conflicts', 'wwylele']	MichaelStollBayreuth assignee:MichaelStollBayreuth	21-59135 21 days ago	52-71238 52 days ago	13-57688 13 days
39162	anovickis author:anovickis	feat(Topology/PartitionOfUnity): add pointwise_decomposition_finsum + companions	Add three short lemmas to `Mathlib/Topology/PartitionOfUnity.lean` extending the existing `PartitionOfUnity` API: - `pointwise_decomposition_finsum` — for `f : X → ℝ` and `x ∈ s`, `f x = ∑ᶠ i, ρ i x · f x`. This is the pointwise step that lifts to integral linearity in measure-theoretic PoU integration: `∫_s f dμ = ∑ᶠ i, ∫_s (ρ i · f) dμ`. - `one_minus_sum_nonneg` — `0 ≤ 1 - ∑ᶠ i, ρ i x`. Direct rearrangement of the existing `sum_le_one` field; useful as a complement-mass remainder bound in chart-by-chart estimates. - `abs_le_one` — `\|ρ i x\| ≤ 1`. Combines the existing `nonneg` and `le_one`; convenience for absolute-value bounds. All three are short proofs using existing structure fields (`sum_eq_one`, `sum_le_one`, `nonneg`, `le_one`). These came up while writing chart-by-chart Stokes-on-manifold estimates where one wants to decompose `∫_M f` into chart-supported pieces using a partition of unity. The pointwise identity is the obvious first step; the other two are complementary algebraic bounds that show up in remainder estimates. --- 🤖 Generated with [Claude Code](https://claude.com/claude-code)	t-topology new-contributor LLM-generated	27/0	Mathlib/Topology/PartitionOfUnity.lean	1	2	['github-actions']	urkud assignee:urkud	21-49252 21 days ago	22-44420 22 days ago	22-44170 22 days
39232	jerwaynejones author:jerwaynejones	feat(Analysis/Complex): residue theorem for rectangular contours	Adds `Mathlib/Analysis/Complex/RectangleResidue.lean` (644 LoC), filling the gap between Cauchy–Goursat for rectangles (`Complex.integral_boundary_rect_eq_zero_of_differentiable_on_off_countable`) and the Cauchy integral formula for circles. The file proves the residue formula for rectangular boundary integrals together with a rotated principal log branch needed to evaluate the left-edge integral that crosses the standard cut. ## Why Mathlib has Cauchy–Goursat for rectangles and the Cauchy integral formula for circles, but no residue theorem for rectangular contours. This file fills that gap. It was extracted from a downstream Lean 4 formalization project (a conditional proof of Goldbach's conjecture, where contour shifting on rectangles arises naturally in Perron's formula). ## Main results - `Complex.hasDerivAt_log_neg` — the rotated logarithm `log_neg z := log (-z) + I * π` has derivative `z⁻¹` on the rotated slit plane `{z \| -z ∈ slitPlane}` (cut on the positive real axis). - `Complex.boundaryIntegral_inv_sub_eq_two_pi_I` — for `ρ` strictly inside the rectangle `[z, w]`, `∮_{∂[z,w]} (s − ρ)⁻¹ ds = 2πi`. - `Complex.boundaryIntegral_eq_residue_sum` — parametric residue theorem for a sum of simple poles plus a holomorphic remainder, packaged as `Complex.RectangleResidueData`. - `Complex.boundaryIntegral_single_pole` — the one-pole specialization. ## Structure The development proceeds in five stages: 1. A notation `Complex.boundaryIntegral` for the oriented boundary integral over `[z, w]`, with a Cauchy–Goursat wrapper and additivity/scaling lemmas. 2. A rotated principal logarithm `Complex.log_neg z := log (-z) + I * π` with cut on the positive real axis, plus its derivative and corner-comparison identities with the standard `Complex.log`. 3. Explicit FTC-based evaluations of the four edge integrals of `(s − ρ)⁻¹`. 4. A closed-form residue boundary integral `∮_{∂[z,w]} (s − ρ)⁻¹ ds = 2πi` for `ρ` strictly inside the rectangle. 5. A parametric residue theorem for sums of simple poles plus a holomorphic remainder, packaged as `Complex.RectangleResidueData`. ## References - L. Ahlfors, Complex Analysis (3rd ed.), §4.5. - E. Stein and R. Shakarchi, Complex Analysis, Ch. 2 §3 Thm 3.1. ## Status Draft while CI verifies the build against current `master` — the file was developed against `v4.28.0` and cherry-picked forward 2942 commits, so import surface changes are possible. Once CI is green I will flip to ready-for-review. 🤖 Generated with [Claude Code](https://claude.com/claude-code)	t-analysis new-contributor	644/0	Mathlib.lean,Mathlib/Analysis/Complex/RectangleResidue.lean	2	2	['github-actions']	nobody	21-30605 21 days ago	unknown	unknown
39165	allenhaozhu author:allenhaozhu	feat(Probability/Moments): add IsSubExponential class	Add `ProbabilityTheory.IsSubExponential X μ ν b`, the sub-exponential random variable class: `mgf X μ s ≤ exp (s²ν/2)` for `\|s\| < 1/b`. Mirror the structure of the existing `Mathlib/Probability/Moments/SubGaussian.lean`. Include constructor lemmas (`IsSubExponential.const`, `mono_b`, `mono_nu`) and a tail bound derived through Mathlib's `measure_ge_le_exp_mul_mgf`. --- ## AI-assistance disclosure Per the Mathlib [AI-use policy](https://leanprover-community.github.io/contribute/index.html#use-of-ai): - Tool. Claude Code (Anthropic) with the Claude Sonnet 4.6 model. - Use. I specified the target lemma statements and the proof strategy; the assistant drafted Lean 4 tactic combinations against current Mathlib. I iterated on the proofs, verified each lemma builds under `lake build` from a clean checkout, and read the final code. - Vouching. I have read every declaration in this file and can defend the proofs without further AI assistance. I welcome reviewer feedback on naming, namespace placement, and stylistic alignment with the surrounding Mathlib modules.	t-measure-probability new-contributor LLM-generated awaiting-author	257/0	Mathlib.lean,Mathlib/Probability/Moments/SubExponential.lean	2	4	['allenhaozhu', 'github-actions', 'grunweg']	nobody	21-10028 21 days ago	22-19671 22 days ago	0-2698 44 minutes
39168	allenhaozhu author:allenhaozhu	feat(Analysis/Convex/Subgradient): add subgradient characterization for \|·\| and ℓ¹	Add `Convex.IsAbsSubgradient x g`, the predicate that `g` is a subgradient of `\|·\|` at `x`. Prove the standard characterization: the only subgradient at `x > 0` is `1`; at `x < 0` it is `-1`; at `x = 0` the subgradients are exactly `[-1, 1]`. Add `IsL1Subgradient`, the componentwise lift to `Fin n → ℝ` used by ℓ¹-regularized estimation (Lasso KKT). --- ## AI-assistance disclosure Per the Mathlib [AI-use policy](https://leanprover-community.github.io/contribute/index.html#use-of-ai): - Tool. Claude Code (Anthropic) with the Claude Sonnet 4.6 model. - Use. I specified the target lemma statements and the proof strategy; the assistant drafted Lean 4 tactic combinations against current Mathlib. I iterated on the proofs, verified each lemma builds under `lake build` from a clean checkout, and read the final code. - Vouching. I have read every declaration in this file and can defend the proofs without further AI assistance. I welcome reviewer feedback on naming, namespace placement, and stylistic alignment with the surrounding Mathlib modules.	t-analysis new-contributor LLM-generated awaiting-author	231/0	Mathlib.lean,Mathlib/Analysis/Convex/Subgradient/Abs.lean	2	4	['allenhaozhu', 'github-actions', 'grunweg']	nobody	21-10026 21 days ago	22-19756 22 days ago	0-2608 43 minutes
38606	dennj author:dennj	feat: preparation for Vanishing Sum of Roots of Unity	Adds the Mathlib API extensions needed for an upcoming formalization of the Lam-style classification theorem for vanishing sums of roots of unity. * Mathlib/LinearAlgebra/LinearIndependent/Lemmas.lean + `exists_eq_const_of_sum_smul_eq_zero_of_sum_eq_zero_of_linearIndependent`: if `∑ vᵢ = 0` and the first `n-1` of `n` vectors are linearly independent, every linear relation has constant coefficients. * Mathlib/RingTheory/Radical/NatInt.lean + `Nat.totient_eq_div_radical_mul_totient_radical`: Euler's totient splits as `φ(n) = (n / rad n) * φ(rad n)`. * Mathlib/RingTheory/RootsOfUnity/PrimitiveRoots.lean + `IsPrimitiveRoot.sum_range_pow_mul_div_eq_zero_of_dvd`: the `d` evenly-spaced powers of a primitive `k`-th root sum to zero, for `d ∣ k` and `1 < d`. * Mathlib/NumberTheory/Cyclotomic/LinearDisjoint.lean (new) + `IsPrimitiveRoot.linearDisjoint_adjoin_pow_of_coprime`: cyclotomic subfields of coprime orders are linearly disjoint over `ℚ`. * Mathlib/NumberTheory/Cyclotomic/LinearRelations.lean (new) + `IsPrimitiveRoot.coeffs_eq_of_sum_pow_eq_zero_prime_coprime`: in the cyclotomic field of order `p * m` with `p` prime coprime to `m`, any `ℚ⟮ζ^p⟯`-linear relation among powers of `ζ^m` has all coefficients equal. --- I need these as preparation to start formalizing the theorem: Let k be a positive integer. If a finite family of complex k-th roots of unity sums to zero, then the size of the family is a non-negative integer combination of the prime divisors of k. --- Human-made PR with AI used for golfing and documentation	new-contributor	219/0	Mathlib.lean,Mathlib/LinearAlgebra/LinearIndependent/Lemmas.lean,Mathlib/NumberTheory/Cyclotomic/LinearDisjoint.lean,Mathlib/NumberTheory/Cyclotomic/LinearRelations.lean,Mathlib/RingTheory/Radical/Totient.lean,Mathlib/RingTheory/RootsOfUnity/PrimitiveRoots.lean	6	3	['github-actions', 'mathlib-merge-conflicts']	nobody	19-84915 19 days ago	19-85000 19 days ago	7-61810 7 days
39279	jayscambler author:jayscambler	feat(Cryptography/Sigma): Schnorr sigma protocol and signature scheme	Adds `Mathlib/Cryptography/Sigma/Schnorr.lean`. New file in a new top-level directory; mathlib currently has no `Mathlib/Cryptography/`, so I've taken `Mathlib/Cryptography/Sigma/` as the natural home for sigma-protocol formalizations. The file proves the three defining properties of Schnorr's identification scheme as a sigma protocol: - `Schnorr.correct`: completeness. Honest verifier accepts honest signer's transcript. - `Schnorr.specialSoundness`: from two accepting transcripts sharing the commitment but using different challenges `c, c'`, the witness `x = (s - s') / (c - c')` is recovered. Needs `q` prime so `c - c'` is invertible in `ZMod q`. - `Schnorr.hvzkAccepts`: the HVZK simulator `g^s · (y^c)⁻¹` always yields accepting transcripts. This is the structural-correctness half of HVZK only; the distributional indistinguishability statement is a separate result and not in this PR. On top of the sigma protocol there's `Schnorr.Signature.{keyGen, sign, verify, correct}` wrapping it as a Fiat-Shamir signature scheme; `Schnorr.Signature.correct` is a one-line corollary of `Schnorr.correct`. Two auxiliary lemmas, `Schnorr.gpow_sub` and `Schnorr.gpow_mul`, bridge `ZMod q` arithmetic and group exponentiation under `Fintype.card G = q`. They're local to this file for now because the surrounding `gpow` API is itself cryptography-specific; if a general `ZMod q`-graded group action framework lands in mathlib later, both lemmas would become instances of it. There's also a small `example` instantiating everything on `Multiplicative (ZMod q)` for `Fact q.Prime` to show the API typechecks. That instantiation is a toy (DLOG is trivial in that group), but it confirms the abstraction is usable. AI disclosure: this PR was a collaboration between myself, Grey Haven's autocontext and Claude Opus 4.7 (Anthropic). I read each line and built locally on current master. (strawberry has three r's)	new-contributor LLM-generated	352/0	Mathlib.lean,Mathlib/Cryptography/Sigma/Schnorr.lean	2	2	['github-actions']	nobody	19-82267 19 days ago	19-81671 19 days ago	19-81421 19 days
38114	javgomzar author:javgomzar	feat(FinitelyPresentedGroup): add finite groups instance	Add IsFinitelyPresented instance for finite groups. Co-authored-by: Hang Lu Su , Thomas Browning --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-group-theory new-contributor large-import	31/2	Mathlib/GroupTheory/FinitelyPresentedGroup.lean,Mathlib/GroupTheory/FreeGroup/Basic.lean	2	33	['github-actions', 'javgomzar', 'kbuzzard', 'mathlib-merge-conflicts', 'plp127', 'tb65536', 'vihdzp']	mattrobball assignee:mattrobball	19-73877 19 days ago	19-72001 19 days ago	42-65930 42 days
31662	edwin1729 author:edwin1729	feat(Topology/Order): topological basis of scott topology on Complete…	…PartialOrder --- [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/.3E.20Algebraic.20complete.20partial.20order.20and.20domain.20theory/with/536359313) for this PR. (2/5) PRs in domain theory, proving that scott topologies over Algebraic DCPOs (`CompletePartialOrder`) are sober. The main reference is [Renata, Duality in Domain Theory](https://alyata.github.io/documents/duality_domain_theory.pdf). But the statements can also be found in the canonical text [Abramsky and Jung](https://www.cs.ox.ac.uk/people/samson.abramsky/handbook.pdf) This first PR proves two prerequisites, namely: - the specialization order induced by the scott topology corresponds to the existing order of the DCPO. Prop 3.1.5 in [Duality in Domain Theory](https://alyata.github.io/documents/duality_domain_theory.pdf) and Prop 2.3.2(1) in [Abramsky and Jung](https://www.cs.ox.ac.uk/people/samson.abramsky/handbook.pdf) - the upward closures of compact elements of the DCPO form a topological basis for the Scott Topology. Prop 3.5.2 in [Duality in Domain Theory](https://alyata.github.io/documents/duality_domain_theory.pdf) and Prop 2.3.6(2) in [Abramsky and Jung](https://www.cs.ox.ac.uk/people/samson.abramsky/handbook.pdf) - [x] depends on: #33061 The next PR is here: #31670 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor awaiting-author	165/1	Mathlib.lean,Mathlib/Order/CompactlyGenerated/Basic.lean,Mathlib/Topology/Order/ScottTopology.lean,Mathlib/Topology/Order/ScottTopologyDCPO.lean,docs/references.bib	5	99	['b-mehta', 'edwin1729', 'github-actions', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'plp127']	b-mehta assignee:b-mehta	19-72778 19 days ago	27-74214 27 days ago	64-15169 64 days
37928	AlexeyMilovanov author:AlexeyMilovanov	refactor(Computability.Encoding): unbundle Γ and remove FinEncoding	This PR unbundles the alphabet `Γ` from the `Encoding` structure and completely removes `FinEncoding`. `Encoding`: The alphabet `Γ` is now an explicit parameter: `structure Encoding (α : Type u) (Γ : Type v)`. `FinEncoding`: Removed. Finiteness is now handled via standard typeclasses (e.g., `[Fintype Γ] (e : Encoding α Γ)`). Combinators: Functions like `finEncodingPair` are simplified to `encodingPair`, dropping the `fin` prefix and `[Fintype]` requirements where no longer needed. Downstream: Mechanically updated `Mathlib.Computability` and `Mathlib.ModelTheory` to pass the explicit `Γ` and use `[Fintype Γ]` where `FinEncoding` was previously required.	new-contributor maintainer-merge	87/67	Mathlib/Computability/Encoding.lean,Mathlib/ModelTheory/Encoding.lean	2	9	['AlexeyMilovanov', 'dagurtomas', 'github-actions', 'vihdzp']	nobody	19-53738 19 days ago	26-18316 26 days ago	51-82853 51 days
36698	ghseeli author:ghseeli	feat(Combinatorics/Enumerative): Latin squares	This PR defines Latin rectangles and Latin squares and proves an extension theorem using Hall's Marriage Theorem. ## Main results - `group_to_cayley_table`: every finite group `G` yields a `LatinSquare G G`. - `latin_rectangle_extends_one_row`: a (non-square) `LatinRectangle` extends to a `LatinRectangle` with one more row. This is an application of Hall's Marriage Theorem, `hallMatchingsOn.nonempty`. - `latin_rectangle_extends_to_latin_square`: a `LatinRectangle` extends to a `LatinSquare`. This is included in a new file `Combinatorics/Enumerative/LatinSquare.lean`. --- - [ ] depends on: #37190 - [ ] depends on: #37720 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-combinatorics blocked-by-other-PR	638/0	Mathlib.lean,Mathlib/Combinatorics/Enumerative/DoubleCounting.lean,Mathlib/Combinatorics/Enumerative/LatinSquare.lean,Mathlib/Combinatorics/Pigeonhole.lean,Mathlib/Data/Fintype/Card.lean,docs/references.bib	6	78	['SnirBroshi', 'cjrl', 'eric-wieser', 'ghseeli', 'github-actions', 'mathlib-dependent-issues', 'vlad902']	nobody	19-51348 19 days ago	59-73968 59 days ago	16-20262 16 days
39341	drocta author:drocta	feat(Algebra/Colimit/DirectLimit): add DirectLimit.(NonUnital)StarAlgebra.(lift/of) maps and associated lemmas	add the `of` and `lift` maps for `DirectLimit.StarAlgebra` and `DirectLimit.NonUnitalStarAlgebra`, as well as the associated lemmas, `of_f`, `lift_comp_of`, `lift_of`, and `hom_ext` for each. Also make `DirectLimit.NonUnitalAlgebra` only require `[Monoid R]` rather than `[CommSemiring R]`. --- Use of AI: I again asked ChatGPT for some advice about some things about this code. I can personally vouch for all of the code I'm submitting, and that I understand all of it. This is the third part of my project towards supporting direct limits of $C^∗$ -algebras (as I described [on Zulip](https://leanprover.zulipchat.com/#narrow/channel/113489-new-members/topic/Early.20feedback.20on.20approach.20towards.20formalizing.20UHF.20algebras.3F) ). This PR adds an import of `Mathlib.Algebra.Star.StarAlgHom` (because it needs `StarAlgHom` and `NonUnitalStarAlgHom`) replacing/encompassing the previously added imports of `Mathlib.Algebra.Star.StarRingHom` and `Mathlib.Algebra.Algebra.NonUnitalHom` (added in PR #38308 and #38672 respectively).	t-algebra new-contributor label:t-algebra$	100/3	Mathlib/Algebra/Colimit/DirectLimit.lean	1	2	['github-actions']	nobody	19-48290 19 days ago	19-47261 19 days ago	19-48557 19 days
37666	TJHeeringa author:TJHeeringa	feat(Analysis/InnerProductSpace/Reproducing): Lipschitz wrt the kernel pseudometric	--- RKHSs $H$ have bounded point evaluations. This induces a pseudometric on the underlying space `X`. The function $f\in H$ are Lipschitz continuous with Lipschitz constant $\\|\|f\\|\|$. This PR puts the pseudometric instance inline. The instance cannot just be put outside the theorem, because that gives problems with resolving type classes / instance synthesis. An alternative to inlining the instance is a type class synonym. One copy would be the RKHS with whatever metric X came equipped with and one copy would be the RKHS with the induced metric. Since there are likely more theorems depending on this pseudometric, I suspect that it is actually a better solution. AI: I had the instance outside the theorem. Lean gave problems with resolving type classes / instance synthesis. I asked Claude and ChatGPT to interpret the error and fix it. The latter just spit gibberish and the former suggested inlining but in a way that didn't work. Then, I asked on Zulip and got the same suggestion but working. The type synonym alternative was also suggested there. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis new-contributor help-wanted	71/6	Mathlib/Analysis/InnerProductSpace/Reproducing.lean	1	3	['TJHeeringa', 'github-actions']	nobody	19-3543 19 days ago	unknown	unknown
33985	YellPika author:YellPika	feat(Order/OmegaCompletePartialOrder): `OmegaCompletePartialOrder` instance for `Sum` with basic `ωScottContinuous` lemmas	This PR adds an `OmegaCompletePartialOrder` instance for `Sum`, along with `ωScottContinuous` lemmas for basic operations (`inl`, `inr`, `elim`). Appropriate lemmas are marked with `@[fun_prop]` so that the `fun_prop` tactic can automatically deduce `ωScottContinuous` proofs for functions involving `Sum`s (e.g. see the proof of `Sum.ωScottContinuous_map`). --- - [x] depends on: #33941 - [x] depends on: #37258 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor large-import t-order awaiting-author	205/3	Mathlib/Data/Sum/Basic.lean,Mathlib/Data/Sum/Order.lean,Mathlib/Order/OmegaCompletePartialOrder.lean,Mathlib/Order/ScottContinuity.lean,Mathlib/Topology/Constructions/SumProd.lean	5	58	['Komyyy', 'Vierkantor', 'YaelDillies', 'YellPika', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'vihdzp']	YaelDillies and pechersky assignee:pechersky assignee:YaelDillies	18-81272 18 days ago	64-21815 64 days ago	52-43778 52 days
37722	SabrinaJewson author:SabrinaJewson	feat(Order/Cover): intervals equal singletons iff	To complement `Set.Icc_eq_singleton_iff`, this introduces: - `Set.Ioc_eq_singleton_iff` / `Set.Ico_eq_singleton_iff` - `Set.Ico_eq_singleton_left_iff` / `Set.Ioc_eq_singleton_right_iff` - `Set.Ioi_eq_singleton_iff` / `Set.Iio_eq_singleton_iff` - `Set.Ioi_eq_singleton_top_iff` / `Set.Iio_eq_singleton_bot_iff` - `Set.Ioo_eq_singleton_iff` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order new-contributor awaiting-author maintainer-merge	39/0	Mathlib/Order/Atoms.lean,Mathlib/Order/Cover.lean	2	16	['Komyyy', 'SabrinaJewson', 'github-actions', 'mathlib-merge-conflicts']	bryangingechen assignee:bryangingechen	18-73229 18 days ago	21-26186 21 days ago	35-7103 35 days
39392	jayscambler author:jayscambler	feat(Cryptography): one-time pad and Shannon perfect secrecy	Adds `Mathlib/Cryptography/OTP.lean`. One-time pad over an arbitrary finite abelian group `G`: - `OTP.encrypt k m := m + k`, `OTP.decrypt k c := c - k`. - `OTP.correct`: `decrypt k (encrypt k m) = m`, by `abel`. - `OTP.perfect_secrecy`: for any `m₀, m₁`, the distributions of `encrypt k m₀` and `encrypt k m₁` over uniform `k` are equal; both reduce to `PMF.uniformOfFintype G`. Proof goes via `Equiv.addLeft`. Independent of the Schnorr PR (#39279); no shared definitions. Unlike everything else likely to live under `Mathlib/Cryptography/`, the security guarantee here is information-theoretic, not computational. AI disclosure: this PR was a collaboration between myself, Grey Haven's autocontext and Claude Opus 4.7 (Anthropic). I read each line and built locally on current master. (strawberry has three r's)	new-contributor LLM-generated	76/0	Mathlib.lean,Mathlib/Cryptography/OTP.lean	2	3	['MrBrain295', 'github-actions']	nobody	18-44819 18 days ago	18-66592 18 days ago	18-66342 18 days
39393	jayscambler author:jayscambler	feat(GameTheory): von Neumann minimax theorem for finite matrix games	Adds `Mathlib/GameTheory/MatrixGame.lean`. Resolves the TODO at `Mathlib/Topology/Sion.lean:48` ("spell out the particular case of von Neumann theorem") by specialising `Sion.exists_isSaddlePointOn` to the bilinear payoff `∑ i j, x i * M i j * y j` on the pair of standard simplices. Two theorems: - `Matrix.exists_saddle_point`: existence of a saddle point in mathlib's `IsSaddlePointOn` convention (`a` minimiser-in-`X`, `b` maximiser-in-`Y`). - `Matrix.exists_mixedNash`: existence of a mixed Nash equilibrium in the textbook matrix-game orientation (row player maximises, column player minimises). Proved by applying Sion to `-payoff M`. Both forms are useful: the first matches mathlib's existing saddle-point machinery, and the second is the statement most game-theory texts use directly. Supporting lemmas: continuity of the payoff in each argument (linear in each), and quasi-convexity / quasi-concavity from `LinearMap.convexOn` / `LinearMap.concaveOn`. The simplex hypotheses for Sion (`Convex`, `IsCompact`, `Nonempty`) come from existing mathlib lemmas (`convex_stdSimplex`, `isCompact_stdSimplex`, `single_mem_stdSimplex`). Creates a new top-level `Mathlib/GameTheory/` directory; mathlib currently has none. A natural follow-up would be a `Mathlib/GameTheory/NormalForm.lean` for general n-player normal-form games and pure Nash equilibrium. AI disclosure: this PR was a collaboration between myself, Grey Haven's autocontext and Claude Opus 4.7 (Anthropic). I read each line and built locally on current master. (strawberry has three r's)	t-topology new-contributor LLM-generated	216/2	Mathlib.lean,Mathlib/GameTheory/MatrixGame.lean,Mathlib/Topology/Sion.lean	3	3	['github-actions', 'vihdzp']	nobody	18-28096 18 days ago	unknown	unknown
22925	ggranberry author:ggranberry	feat(Mathlib/PlaceHolder/ToeplitzHausdorff): Toeplitz-Hausdorff	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP new-contributor will-close-soon awaiting-author help-wanted t-analysis	411/0	Mathlib/PlaceHolder/ToeplitzHausdorff.lean,Mathlib/PlaceHolder/ToeplitzHausdorff_v2.lean	2	16	['AntoineChambert-Loir', 'faenuccio', 'ggranberry', 'github-actions', 'vihdzp']	faenuccio assignee:faenuccio	18-6623 18 days ago	unknown	unknown
39270	m13683320924-hue author:m13683320924-hue	feat: prove strict group homs are stable under Prod.map	This PR proves that strict group homomorphisms are stable under product maps. It adds an auxiliary lemma showing that the range restriction of a strict group homomorphism is an open quotient map, and uses it to prove that `MonoidHom.prodMap` preserves `Topology.IsStrictMap`. Towards #38421.	t-topology new-contributor	44/0	Mathlib/Topology/Algebra/Group/Basic.lean	1	7	['eric-wieser', 'github-actions', 'm13683320924-hue']	nobody	17-77376 17 days ago	unknown	unknown
39456	BMMilligan1 author:BMMilligan1	feat(Probability/PMF): advantageFromHalf for Bool-valued PMFs	This PR adds `PMF.advantageFromHalf : PMF Bool → ℝ`, defined as `2 * (p true).toReal - 1`, together with API lemmas covering bounds (`_le_one`, `_neg_one_le`), the zero-advantage characterization (`_eq_zero_iff_half`), `PMF.map` composition (`_map_tsum`), and canonical witness evaluations on `uniformOfFintype Bool`, `pure true`, and `pure false`. ## Motivation The "advantage from half" of a Bernoulli-like distribution is the signed gap of the `true`-probability away from `1/2`, rescaled to `[-1, 1]`. It is the natural decision-algorithm advantage notion in computational complexity: when a heuristic `H : α → Bool` is post-composed with a `PMF α` via `PMF.map`, the resulting `PMF Bool`'s `advantageFromHalf` is the advantage of `H` as a decision procedure on the source distribution. Concretely, the definition supports formalizations of Hirahara 2018 (FOCS, [arXiv:1808.06974](https://arxiv.org/abs/1808.06974)) Theorem 1.1's worst-case-to-average-case reduction for Gap-MCSP, where the heuristic algorithm's advantage `ε(n) = 1/poly(n)` over the uniform truth-table distribution is the load-bearing quantity. The current Mathlib `PMF` library supports `PMF.uniformOfFintype` (see `Mathlib/Probability/Distributions/Uniform.lean`) but lacks the bias-from-half notion at this signature. ## API summary - `PMF.advantageFromHalf : PMF Bool → ℝ` - `PMF.advantageFromHalf_le_one` (`@[simp]`) - `PMF.advantageFromHalf_neg_one_le` (`@[simp]`) - `PMF.advantageFromHalf_eq_zero_iff_half` - `PMF.advantageFromHalf_map_tsum` - `PMF.advantageFromHalf_uniformBool` (witness: advantage 0) - `PMF.advantageFromHalf_pure_true` (witness: advantage 1) - `PMF.advantageFromHalf_pure_false` (witness: advantage -1) ## Notes * The file lives at `Mathlib/Probability/ProbabilityMassFunction/Advantage.lean`, alphabetically before `Basic.lean`, and is imported in `Mathlib.lean` at the corresponding alphabetical position. * All proofs are sorry-free. * The definition is `noncomputable` (matches `PMF` style; `(p true).toReal` threading through `ENNReal`). * No new imports outside the existing PMF / ENNReal substrate. * Maintainer review of the naming (`advantageFromHalf` vs alternative candidates like `biasFromHalf`) and of whether the `tsum`-form composition lemma should be supplemented by a `Finset.sum` variant for `Fintype` sources is most welcome. Co-authored-by: Claude Opus 4.7 (1M context)	t-measure-probability new-contributor	120/0	Mathlib.lean,Mathlib/Probability/ProbabilityMassFunction/Advantage.lean	2	2	['github-actions']	nobody	17-45332 17 days ago	unknown	unknown
37707	MavenRain author:MavenRain	feat(Combinatorics/SimpleGraph): add IsMaximalClique/IsMaximalIndepSet, refactor IsMaximum* to MaximalFor	Addresses #34962	new-contributor t-combinatorics	63/31	Mathlib/Combinatorics/SimpleGraph/Clique.lean	1	6	['MavenRain', 'SnirBroshi', 'eric-wieser', 'github-actions']	nobody	17-28542 17 days ago	17-27959 17 days ago	17-27709 17 days
37720	cjrl author:cjrl	feat(Data/Fintype/Card): existsUnique_notMem_image_of_injective_of_card_succ	This pull requests adds a small theorem `existsUnique_notMem_image_of_injective_of_card_succ` to `Mathlib/Data/Fintype/Card` that says given an injective map f : α → β such that β has cardinality one more than α, there exists a unique element of β not in the image of f. This can be viewed as going in the opposite direction of `card_lt_of_injective_of_notMem`. This little fact is needed for our Latin Square PR #36698. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor t-set-theory	19/0	Mathlib/Data/Finset/Card.lean,Mathlib/Data/Fintype/Card.lean	2	10	['IvanRenison', 'cjrl', 'dagurtomas', 'ghseeli', 'github-actions']	nobody	16-45522 16 days ago	16-45522 16 days ago	54-5231 54 days
26479	thefundamentaltheor3m author:thefundamentaltheor3m	feat(Analysis/Complex/CauchyIntegral): Cauchy–Goursat for Unbounded Rectangles	In this PR, we prove versions of the Cauchy-Goursat theorem where the contours in question are rectangular and unbounded (ie, where the contours look like the $\bigsqcup$ symbol). I am not sure if I have formalised these in the best way, or if `Analysis.Complex.CauchyIntegral` is the best place for them (it might be prudent to reorganise the file into multiple files at some point), but I believe this is a useful result. Suggestions welcome. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-analysis sphere-packing	219/0	Mathlib/Analysis/Complex/CauchyIntegral.lean	1	7	['github-actions', 'j-loreaux', 'loefflerd', 'mathlib4-merge-conflict-bot', 'thefundamentaltheor3m', 'wwylele']	urkud assignee:urkud	15-36357 15 days ago	15-36357 15 days ago	49-46055 49 days
35122	Marygold-Dusk author:Marygold-Dusk	feat: define C^n submersions	This PR defines submersions between C^n manifolds. In the infinite-dimensional setting, submersions are defined via local normal forms rather than surjectivity of the mfderiv. A map f is a submersion at x if, in suitable charts around x and f x, it has the form (u, v) ↦ u after identifying the model space with a product. We prove a few basic properties: - being a submersion is a local property, - products of submersions are submersions, - the set of submersed points is open Future PRs will prove that submersions are C^n and deduce equivalence with the standard definition in finite dimensions. From the path towards the regular value theorem. This file was developed under the supervision of Michael Rothgang. Co-authored-by: Michael Rothgang --- Most of the design is analogues to immersions.	t-differential-geometry new-contributor	642/0	Mathlib.lean,Mathlib/Geometry/Manifold/Submersion.lean,docs/references.bib	3	54	['Marygold-Dusk', 'chrisflav', 'github-actions', 'grunweg']	PatrickMassot and grunweg assignee:grunweg assignee:PatrickMassot	15-24545 15 days ago	15-24545 15 days ago	59-39431 59 days
37010	pion2024 author:pion2024	`Sl2`update: add theorem `finrank_weightSpace_eq_one_of_isIrreducible`	# Background: I am a 2nd year undergrad student in mathematics currently self-teaching Lie algebra and representation theory. Before starting the formalization, I searched for related keywords on Zulip and in the GitHub issues and commits. As far as I could tell, there were no existing results or ongoing attempts before I started. All feedback is welcome. Even a quick check on the statement design/an idea on the generalization (cf Limitations below) would be incredibly helpful. # Overview In this PR, I added the new section `IsAlgClosedIrreducible` which formalizes the well-known theorem `finrank_weightSpace_eq_one_of_isIrreducible` for the Lie algebra $\mathfrak{sl}_2$ step by step. It proves that for a finite-dimensional irreducible representation of $\mathfrak{sl}_2$ over an algebraically closed field $K$ of characteristic zero, every non-trivial weight space has a dimension of exactly 1. # Formalization Structure : Instead of relying on explicit finite sums (`Finset.sum`) and manipulating coefficients, I heavily leverage Mathlib's abstractions in Submodule Lattice Theory and Coordinate-free Linear Algebra. The formalization proceeds in the following logic: 1. Existence of a Primitive Vector (`exists_primitiveVector`): I construct a primitive (highest-weight) vector by showing that repeated applications of the raising operator $e$ must eventually yield zero due to the finite-dimensionality of $M$ and the linear independence of eigenvectors corresponding to distinct eigenvalues. 2. The span of $f$-Tower as a Lie Submodule equals to the whole space (`fTowerLieSubmodule_eq_top`): I define the $f$-tower submodule as the $K$-span of $\{f^k m \mid k \in \mathbb{N}\}$. By proving its closure under the action of $f, h$, and $e$, I establish it as a Lie submodule. Since $M$ is irreducible, this submodule must be the entire space ($\top$). 3. Submodule Lattice Operations (`exists_mem_fTower_of_weightSpace_ne_bot`): To prove that every weight in $M$ is of the form $\mu_0 - 2k$, I use lattice operations (iSup, inf, and Disjoint) to avoid element-wise tracking. Since the $f$-tower spans $M$, the supremum of its weight spaces is $\top$. By leveraging `Module.End.eigenspaces_iSupIndep`, I show that any arbitrary non-trivial weight space would have a trivial intersection with $\top$ if its weight didn't belong to the sequence, yielding a contradiction. 4. Dimension Calculation via Basis Equivalence (`finrank_weightSpace_eq_one_of_isIrreducible`): Finally, I construct a basis from the non-zero elements of the $f$-tower. To show the weight space is 1-dimensional, I use `Basis.equivFun` to compare coefficients algebraically. This avoids heavy manual indexing and index-shifting, proving that any vector in the weight space $\mu_0 - 2k$ is merely a scalar multiple of $f^k m$. # Use of AI: I used Gemini 3.1 Pro for tactics, theorems, improvement suggestions, and error explanations. I fully understand and can vouch for all the modifications I have made to the file. # Limitations: I only managed to formalize the finite-dimensional version, although the theorem also holds in the infinite-dimensional case. In the infinite case the existence of a primitive vector is not guaranteed. A quick search suggests that we might need heavy tools like Casimir operators and the universal enveloping algebra, which are totally beyond my current level. I am looking into it, but since there is a significant mathematical gap, I thought it would be best to get this finite-dimensional version merged first.	new-contributor t-algebra large-import awaiting-author merge-conflict label:t-algebra$	336/0	Mathlib/Algebra/Lie/Sl2.lean	1	11	['github-actions', 'mathlib-bors', 'mathlib-merge-conflicts', 'ocfnash', 'pion2024']	ocfnash assignee:ocfnash	15-16121 15 days ago	61-83158 61 days ago	2-56148 2 days
36832	KryptosAI author:KryptosAI	chore(Data/Finset/Card): rename `pred_card_le_card_erase` to `sub_one_card_le_card_erase`	## Summary The name `pred_card_le_card_erase` suggests `Nat.pred` but the statement uses `- 1` (i.e., `Nat.sub 1`). Rename to `sub_one_card_le_card_erase` to match the actual statement. A deprecated alias is added for backwards compatibility. ### Files changed - `Mathlib/Data/Finset/Card.lean` — definition renamed + deprecated alias - `Mathlib/Data/Finset/Powerset.lean` — reference updated - `Mathlib/Combinatorics/Additive/SubsetSum.lean` — reference updated - `Mathlib/Algebra/Polynomial/EraseLead.lean` — reference updated Addresses the `Finset.pred_card_le_card_erase` item in #21584. ## AI disclosure I used Claude Code to explore the codebase (finding all references to rename) and to draft the PR description. I reviewed and understand all changes — these are straightforward renames with a deprecated alias.	new-contributor awaiting-author	22/15	Mathlib/Algebra/Polynomial/EraseLead.lean,Mathlib/Combinatorics/Additive/SubsetSum.lean,Mathlib/Combinatorics/SetFamily/AhlswedeZhang.lean,Mathlib/Combinatorics/SetFamily/Shadow.lean,Mathlib/Data/Finset/Card.lean,Mathlib/Data/Finset/Powerset.lean,Mathlib/Data/Set/Card.lean,Mathlib/GroupTheory/Perm/Support.lean,Mathlib/RingTheory/Ideal/Operations.lean	9	8	['KryptosAI', 'Multramate', 'dagurtomas', 'github-actions', 'mattrobball', 'ooovi']	nobody	15-8565 15 days ago	15-8565 15 days ago	59-40608 59 days
39216	emlis42 author:emlis42	feat(Topology/Algebra/InfiniteSum): add `limUnder_eq_tprod`	This PR adds `limUnder_eq_tprod` and `limUnder_eq_tsum`.	t-topology new-contributor	10/0	Mathlib/Topology/Algebra/InfiniteSum/Defs.lean	1	6	['SnirBroshi', 'emlis42', 'github-actions', 'grunweg', 'mathlib-bors']	urkud assignee:urkud	14-82748 14 days ago	14-82750 14 days ago	6-77531 6 days
32555	ksenono author:ksenono	feat(Combinatorics/SimpleGraph/Matching): maximum and maximal matchings for Konig's theorem	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor awaiting-author	112/0	Mathlib/Combinatorics/SimpleGraph/DegreeSum.lean,Mathlib/Combinatorics/SimpleGraph/Matching.lean	2	46	['SnirBroshi', 'SproutSeeds', 'YaelDillies', 'b-mehta', 'github-actions', 'jcommelin', 'ksenono']	YaelDillies assignee:YaelDillies	14-82187 14 days ago	15-9946 15 days ago	130-25196 130 days
39269	godofecht author:godofecht	feat(Algebra/Spectrum): add the second resolvent identity	Adds `spectrum.resolvent_sub_resolvent`: For `a b : A` in an `R`-algebra and `r` in the resolvent set of both, `resolvent a r - resolvent b r = resolvent a r * (a - b) * resolvent b r`. Companion to `spectrum.resolvent_eq`.	t-algebra new-contributor label:t-algebra$	15/0	Mathlib/Algebra/Algebra/Spectrum/Basic.lean	1	3	['github-actions', 'wwylele']	nobody	14-80739 14 days ago	14-79489 14 days ago	20-63944 20 days
39366	akiezun author:akiezun	feat(Data/Nat): add prime divisibility for ascFactorial and choose	Adds two prime-divisibility lemmas for natural-number factorial/binomial APIs. The first characterizes when a prime divides an ascending factorial: `Nat.Prime.dvd_ascFactorial_iff`. The second applies this to binomial coefficients: `Nat.Prime.dvd_choose_add_sub_one_iff`, using `Nat.ascFactorial_eq_factorial_mul_choose'` and cancellation of the `n!` factor when `n < p`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor large-import	46/0	Mathlib.lean,Mathlib/Data/Nat/Choose/Consecutive.lean,Mathlib/Data/Nat/Factorial/BigOperators.lean	3	9	['SnirBroshi', 'akiezun', 'github-actions', 'wwylele']	nobody	14-73286 14 days ago	14-74002 14 days ago	18-80778 18 days
37584	kennethgoodman author:kennethgoodman	feat(Data/Nat/Fib): formalize Lamé's theorem	## Summary Formalize [Lamé's theorem](https://en.wikipedia.org/wiki/Lam%C3%A9%27s_theorem) (1844), the founding result of computational complexity theory. Lamé's Theorem: If the Euclidean algorithm on inputs `(a, b)` with `b ≤ a` takes `n + 1` division steps, then `b ≥ fib(n + 1)` and `a ≥ fib(n + 2)`. ### New definitions - `Nat.euclidSteps`: counts the number of division steps in the Euclidean algorithm on natural number inputs. ### New theorems - `Nat.fib_le_of_euclidSteps`: the main Lamé bound — Fibonacci lower bound on inputs given a step count. - `Nat.euclidSteps_le_of_lt_fib`: the contrapositive — step count upper bound given a Fibonacci bound on the smaller input. - `Nat.add_mod_le`: helper lemma that `b + a % b ≤ a` when `b ≤ a` and `0 < b`. ### Proof strategy Induction on `n`, tracking both elements of the pair. The key insight is that each Euclidean step replaces `(a, b)` with `(b, a % b)`, and since `a ≥ b + a % b` (because `a / b ≥ 1`), the Fibonacci recurrence `fib(n+3) = fib(n+2) + fib(n+1)` matches the structure of the algorithm. ### References - Gabriel Lamé, Note sur la limite du nombre des divisions dans la recherche du plus grand commun diviseur entre deux nombres entiers, Comptes rendus de l'Académie des sciences, 1844. --- ### AI usage disclosure Per the [Mathlib AI guidelines](https://leanprover-community.github.io/contribute/index.html#use-of-ai): Claude Code (Claude Opus 4.6) was used to assist with writing the Lean 4 proof code, fixing tactic errors, and drafting this PR description. The mathematical proof (induction on step count, tracking both pair elements through the Fibonacci recurrence) was designed by hand and verified on paper before formalization. I have reviewed and understand every line of the resulting Lean code and can explain all proof steps. --- - [x] builds cleanly (`lake build Mathlib.Data.Nat.Fib.Lame`) - [x] no `sorry` - [x] lines ≤ 100 characters, no trailing whitespace - [x] `autoImplicit false` - [x] docstrings on all public declarations	new-contributor LLM-generated t-data merge-conflict	121/0	Mathlib.lean,Mathlib/Data/Nat/Basic.lean,Mathlib/Data/Nat/Fib/Basic.lean,Mathlib/Data/Nat/Fib/Lame.lean,docs/1000.yaml	5	25	['euprunin', 'github-actions', 'kennethgoodman', 'mathlib-merge-conflicts', 'vihdzp', 'wwylele']	TwoFX assignee:TwoFX	14-69059 14 days ago	14-69060 14 days ago	44-53174 44 days
29744	espottesmith author:espottesmith	feat(Combinatorics): define directed hypergraphs	This PR defines directed hypergraphs: ``` @[ext] structure DiHypergraph (α : Type*) where /-- The vertex set -/ vertexSet : Set α /-- The edge set -/ edgeSet : Set ((Set α) × (Set α)) /-- Each edge is a pair (s, d), where s ⊆ vertexSet and d ⊆ vertexSet -/ edge_src_dst_isSubset_vertexSet' : ∀ ⦃e⦄, e ∈ edgeSet → e.1 ⊆ vertexSet ∧ e.2 ⊆ vertexSet ``` Additional definitions: - tail/head stars and negative/positive stars - some special cases (B-Graph, F-Graph, BF-Graph, and what I'm calling a "non-endless" dihypergraph, where neither the source/tail nor the destination/head are empty) - Vertex and (hyper)edge adjacency - isolated vertices - empty and nonempty dihypergraphs The design employed here is based off of #28613, but this PR does not depend on that one. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	398/0	Mathlib.lean,Mathlib/Combinatorics/DiHypergraph/Basic.lean	2	4	['b-mehta', 'espottesmith', 'github-actions', 'mathlib4-merge-conflict-bot']	nobody	14-50149 14 days ago	23-18813 23 days ago	117-84033 117 days
36274	JTylM author:JTylM	feat(Combinatorics/SimpleGraph/Matching): implemented the matchingNumber of a graph	--- - [ ] depends on: #36406 - [ ] depends on: #32555 I implemented the matchingNumber as described in the issue and proved some statements including showing that there exists a matching achieving the matchingNumber. matchingNumber is increasing under injective maps matchingNumber is equal under isomorphisms matchingNumber of a matching is the cardinality of the matching This is my first PR and i had some trouble with some of the proofs, especially with the proof for matchingNumber.isAttained. So any suggestions on how to make the proofs shorter would be welcome. Also i was not sure about the naming of some of the theorems so i would apprechiate feedback here as well.	new-contributor t-combinatorics blocked-by-other-PR merge-conflict	292/2	Mathlib/Combinatorics/SimpleGraph/Matching.lean	1	40	['JTylM', 'SnirBroshi', 'SproutSeeds', 'github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'vlad902']	nobody	14-48909 14 days ago	75-2698 75 days ago	8-58058 8 days
39569	AlexBrodbelt author:AlexBrodbelt	feat(Mathlib/Data/Finite/Units): Units are (in)finite if type is (in)finite	Shows - [ ] depends on: #39568 - [ ] depends on: #39567 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	blocked-by-other-PR t-data new-contributor	75/0	Mathlib.lean,Mathlib/Data/Finite/Option.lean,Mathlib/Data/Finite/Subtype.lean,Mathlib/Data/Finite/Units.lean	4	3	['github-actions', 'mathlib-dependent-issues']	nobody	14-10069 14 days ago	unknown	unknown
39567	AlexBrodbelt author:AlexBrodbelt	feat(Mathlib/Data/Finite/Option): option type is finite iff type is finite	Option type is finite if and only if the type is finite. This is an intermediate result to proving that if the `GroupWithZero` is (in)finite then the `Units` are (in)finite. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor	25/0	Mathlib.lean,Mathlib/Data/Finite/Option.lean	2	11	['AlexBrodbelt', 'github-actions', 'plp127', 'themathqueen']	nobody	14-1421 14 days ago	14-843 14 days ago	14-15302 14 days
39568	AlexBrodbelt author:AlexBrodbelt	feat(Mathlib/Data/Finite/Subtype): Subtype of elements not equal to a term is finite iff type is finite	Subtype of terms not equal to a term is finite iff type is finite. This is an intermediate result to prove that if a `GroupWithZero` is (in)finite then the `Units` are (in)finite. - [ ] depends on: #39567 [shows option type is finite iff type is finite] --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor blocked-by-other-PR	45/0	Mathlib.lean,Mathlib/Data/Finite/Option.lean,Mathlib/Data/Finite/Subtype.lean	3	5	['AlexBrodbelt', 'github-actions', 'mathlib-dependent-issues', 'themathqueen']	nobody	13-86105 13 days ago	14-15295 14 days ago	0-1230 20 minutes
37350	aditya-ramabadran author:aditya-ramabadran	feat(Analysis/Distribution): define canonical maps between Schwartz/test functions, distributions/tempered distributions	Defines these canonical maps: (1) continuous linear map from $\mathcal D$ to $\mathcal S$, and (2) induced (linear) restriction map from $\mathcal S'$ to $\mathcal D'$, as assigned by @ADedecker. --- Put in a separate file since Distribution.lean only imports TestFunction right now and I thought it was cleaner to do in a new bridge file with both the maps. Open to changing this though. * Made use of #36445 (proved first map locally on fixed support spaces first by local seminorm estimates, then used limitCLM) * Needed a real to complex bridge `TestFunction.ToComplexSchwartzMap` since distributions are defined on real-valued test functions but tempered distributions in mathlib are defined on complex-valued Schwartz functions * Induced map $\mathcal S'(E,F) \to \mathcal D'(Ω,F)$ is $\mathbb C$-linear The main important defs are `ContDiffMapSupportedIn.toSchwartzMapCLM` which is the local fixed-support part, then `TestFunction.toSchwartzMapCLM` (where the continuity uses limitCLM to glue the local continuous linear maps on each $\mathcal D_K$), and `TemperedDistribution.toDistributionLM` which is the linear map from tempered distributions to ordinary distributions. Tested with `lake env lean Mathlib/Analysis/Distribution/TestFunctionSchwartz.lean` [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-analysis new-contributor	225/0	Mathlib.lean,Mathlib/Analysis/Distribution/TestFunctionSchwartz.lean	2	24	['aditya-ramabadran', 'github-actions', 'j-loreaux']	ADedecker and mcdoll assignee:mcdoll assignee:ADedecker	13-79780 13 days ago	19-77874 19 days ago	51-73256 51 days
33786	hdmkindom author:hdmkindom	feat(Analysis/Matrix): add Jacobian matrix for matrix-valued functions	This PR introduces the Jacobian matrix for matrix-valued functions `F : Matrix m n 𝕜 → Matrix p q 𝕜`. The Jacobian matrix `jacobianMatrix F X` at point `X` is indexed by `(p × q) × (m × n)`, where each entry represents the partial derivative with respect to a basis element. To handle instance-mismatch issues with matrix norms, we use local Frobenius norm instances. This PR adds the new file: 'Analysis/Matrix/Jacobian.lean' ## Main definitions - `jacobianMatrix F X`: The Jacobian matrix at point `X`, defined by `jacobianMatrix F X (i, k) (j, l) = (fderiv ℝ F X (Matrix.single j l 1)) i k` ## Main theorems - `fderiv_eq_jacobian_mul`: Express the Fréchet derivative as a contraction with the Jacobian - `jacobianMatrix_comp`: Chain rule for Jacobian matrices - `jacobianMatrix_linear`, `jacobianMatrix_id`, `jacobianMatrix_const`: Basic properties - `jacobianMatrix_add`, `jacobianMatrix_smul`: Linearity properties	t-analysis new-contributor awaiting-author	174/0	Mathlib.lean,Mathlib/Analysis/Matrix/Jacobian.lean	2	21	['erdOne', 'github-actions', 'hdmkindom', 'jcommelin']	sgouezel assignee:sgouezel	13-78907 13 days ago	104-85349 104 days ago	39-33087 39 days
34713	dennj author:dennj	feat(Probability/Markov): stationary distributions for stochastic matrices	This PR proves that every row-stochastic matrix on a finite nonempty state space has a stationary distribution in the standard simplex. Main additions to `Mathlib/Probability/Markov/Stationary.lean`: - `IsStationary`: A distribution μ is stationary for matrix P if μ ᵥ* P = μ - `cesaroAverage`: Cesàro average of iterates of a vector under a matrix - `Matrix.rowStochastic.exists_stationary_distribution`: existence theorem The proof uses Cesàro averaging: start with uniform distribution, form averages, extract convergent subsequence by compactness, show limit is stationary via L¹ non-expansiveness. Also adds `vecMul_mem_stdSimplex` to `Stochastic.lean`: multiplying a probability vector by a row-stochastic matrix preserves simplex membership. This is human-made PR with AI help in golfing proof and documenting the code.	new-contributor t-measure-probability	166/0	Mathlib.lean,Mathlib/LinearAlgebra/Matrix/Stochastic.lean,Mathlib/Probability/Markov/Stationary.lean	3	17	['EtienneC30', 'dennj', 'dupuisf', 'github-actions', 'grunweg', 'j-loreaux', 'mathlib-merge-conflicts', 'riccardobrasca']	kex-y assignee:kex-y	13-48614 13 days ago	20-79874 20 days ago	47-727 47 days
38014	cduenasnavarro author:cduenasnavarro	feat(InformationTheory): linear codes over finite fields and minimum distance properties	Define linear codes over a finite field `F` as finite-dimensional subspaces of `Fin n → F`, together with their minimum Hamming distance. Main definitions: * `LinearCode` * `minDist` * `LinearCodeWithDist` * `hammingSphere` Main results: * `minDist_eq_sInf_pairwiseDist`: characterisation of the minimum distance via pairwise distances * `disjoint_spheres`: Hamming spheres of radius `t` around distinct codewords are disjoint if `2 * t < d` Pending: * Choosing an adequate book reference --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-measure-probability new-contributor	181/0	Mathlib.lean,Mathlib/InformationTheory/Coding/LinearCode.lean	2	37	['cduenasnavarro', 'github-actions', 'linesthatinterlace', 'rkirov', 'vihdzp', 'wwylele']	kex-y assignee:kex-y	13-48610 13 days ago	17-8746 17 days ago	49-62203 49 days
39384	EngelsVon author:EngelsVon	feat(Analysis/Calculus/DifferentialForm): Stokes' theorem on rectangular boxes	## Summary This PR proves the generalized Stokes theorem for differential forms on rectangular boxes $[a, b] \subset \mathbb{R}^{m+1}$. The proof strategy is: 1. Extract the `i`-th signed face component `boxFaceComponent ω i` from an `m`-form `ω` — a scalar function whose divergence equals the top-form density of the exterior derivative `dω`. 2. Apply Mathlib's existing divergence theorem for boxes (`integral_divergence_of_hasFDerivAt_off_countable'`). This gives a genuine proved Stokes formula in the Euclidean setting, complementing the existing infrastructure for differential forms. ## Main definitions - `DifferentialForm.topFormDensity`: density function of a top-form field - `DifferentialForm.boxFaceComponent`: the `i`-th signed face component of an `m`-form on `ℝ^(m+1)` - `DifferentialForm.boxBoundaryIntegral`: the signed boundary integral over `∂[a,b]` ## Main results - `box_stokes_of_hasFDerivAt`: Stokes' theorem on boxes with pointwise differentiability hypotheses - `box_stokes_of_contDiff`: a convenient `C¹` formulation	t-analysis new-contributor	314/0	Mathlib.lean,Mathlib/Analysis/Calculus/DifferentialForm/BoxStokes.lean	2	2	['github-actions']	j-loreaux assignee:j-loreaux	13-48601 13 days ago	18-74965 18 days ago	18-74715 18 days
39389	i-love-lean author:i-love-lean	feat(Analysis/SpecialFunctions): homeomorphism for spherical coordinates	A few months ago, I noticed that mathlib was missing change of variables to spherical coordinates, which is taught in undergraduate calculus and useful for many 3D integrals. So far, I used `PolarCoord.lean` as reference and implemented a similar homeomorphism for spherical coordinates. There's still a lot of work left to prove an analog of `integral_comp_polarCoord_symm` but for spherical coordinates, so I'm splitting up the work into several PRs. I also fixed a typo in `PolarCoord.lean`.	t-analysis new-contributor	133/2	Mathlib.lean,Mathlib/Analysis/SpecialFunctions/Complex/Arg.lean,Mathlib/Analysis/SpecialFunctions/PolarCoord.lean,Mathlib/Analysis/SpecialFunctions/SphericalCoord.lean	4	4	['github-actions', 'i-love-lean', 'wwylele']	j-loreaux assignee:j-loreaux	13-48600 13 days ago	18-66045 18 days ago	18-65795 18 days
39406	roos-j author:roos-j	feat(Analysis): van der Corput's lemma	Adds van der Corput's lemma on one-dimensional oscillatory integrals, a standard tool in harmonic analysis. Co-authored-by: Manasa Praveen --- From https://github.com/roos-j/lean-oscillatory, see there for future plans Zulip discussion [#mathlib4 > Oscillatory integrals in Lean](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Oscillatory.20integrals.20in.20Lean/with/584786060) AI disclosure: The code in this PR was predominantly human-written. gpt-5.5 has helped in the later stages with shortening proofs, golfing and general advice.	t-analysis new-contributor	551/0	Mathlib.lean,Mathlib/Analysis/OscillatoryIntegrals/VanDerCorput.lean	2	2	['github-actions']	j-loreaux assignee:j-loreaux	13-48598 13 days ago	18-7077 18 days ago	18-6827 18 days
34703	martinwintermath author:martinwintermath	Generalizing orthogonalBilin	--- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor merge-conflict	51/25	Mathlib/Analysis/InnerProductSpace/Orthogonal.lean,Mathlib/LinearAlgebra/QuadraticForm/Basic.lean,Mathlib/LinearAlgebra/SesquilinearForm/Basic.lean	3	2	['github-actions', 'mathlib-merge-conflicts']	nobody	13-45065 13 days ago	unknown	unknown
38369	quantumsnow author:quantumsnow	feat(AlgebraicTopology): Eilenberg Steenrod axioms	This introduces the Eilenberg-Steenrod axioms for a homology theory. --- - [x] depends on: #36621 - [ ] depends on: #39236 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-algebraic-topology blocked-by-other-PR	365/0	Mathlib.lean,Mathlib/AlgebraicTopology/EilenbergSteenrod.lean,Mathlib/Topology/Category/TopCat/Basic.lean,Mathlib/Topology/Category/TopPair.lean	4	38	['chrisflav', 'github-actions', 'joelriou', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'quantumsnow']	nobody	13-14401 13 days ago	21-20697 21 days ago	3-41971 3 days
39605	Qinghev author:Qinghev	Add docstrings for reversed range telescoping lemmas	This PR adds docstrings for two existing Finset telescoping lemmas and their additive versions generated by `to_additive`: * `Finset.prod_range_div'` / `Finset.sum_range_sub'` * `Finset.eq_prod_range_div` / `Finset.eq_sum_range_sub` The goal is a small documentation-only contribution that makes the reversed range telescoping API easier to discover from search and hover docs. Local checks: * `git diff --check -- Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean` * Attempted `lake env lean Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean`, but local validation is currently blocked by downloading the `leanprover/lean4:v4.30.0-rc2` toolchain from GitHub timing out/connection-resetting on this machine. Opened as draft until the toolchain/network check can be completed or CI confirms the documentation-only change.	t-algebra new-contributor label:t-algebra$	8/2	Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean	1	2	['github-actions']	nobody	13-11703 13 days ago	13-11703 13 days ago	13-11453 13 days
39332	Michaillus author:Michaillus	chore(Topology/Spectral): Added two small lemmas	chore(Topology/Spectral): Added two lemmas `IsCompact.isClosed_constructibleTopology_of_isOpen` `IsCompact.isClosed_constructibleTopology_of_isClosed` --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor	12/0	Mathlib/Topology/Spectral/ConstructibleTopology.lean	1	7	['Michaillus', 'github-actions', 'plp127', 'qawbecrdtey']	PatrickMassot assignee:PatrickMassot	13-8197 13 days ago	19-61927 19 days ago	19-61677 19 days
39225	junodeveloper author:junodeveloper	feat(SimpleGraph): add no-bridge theorem for even degree graphs	This PR proves that a finite graph in which every vertex has even degree has no bridge. It adds: * `SimpleGraph.not_isBridge_of_even_degree` The proof argues by contradiction: if an edge is a bridge, delete it and look at the connected component containing one endpoint. In that component, the endpoint has odd degree, while any other odd-degree vertex would contradict the bridge assumption and the even-degree hypothesis. This contradicts the handshaking lemma via the existing odd-degree API. Local checks: ```bash lake build Mathlib.Combinatorics.SimpleGraph.Connectivity.EdgeConnectivity lake exe lint-style Mathlib.Combinatorics.SimpleGraph.Connectivity.EdgeConnectivity lake exe runLinter Mathlib.Combinatorics.SimpleGraph.Connectivity.EdgeConnectivity ``` ## AI usage disclosure I used OpenClaw/Codex while developing this PR. Much of the Lean proof of `not_isBridge_of_even_degree` was drafted with AI assistance, including API search and proof refactoring. I reviewed the generated code, made edits, ran the local checks above, and understand and take responsibility for the final statement and proof.	t-combinatorics new-contributor large-import LLM-generated	122/0	Mathlib/Combinatorics/SimpleGraph/Connectivity/EdgeConnectivity.lean	1	12	['Rida-Hamadani', 'SnirBroshi', 'github-actions', 'junodeveloper', 'linesthatinterlace']	nobody	13-2968 13 days ago	13-46328 13 days ago	21-55749 21 days
39607	TentativeConvert author:TentativeConvert	feat(Algebra/DirectSum): equivalence between direct sum indexed by ι₁ and double sum indexed by ι₂ and fibres of f : ι₁ → ι₂	1. Add variant `equivCongrLeft'` of `equivCongrLeft`, and corresponding `…_apply` lemma. 2. Add `…_of lemmas` for both `equivCongrLeft` and `equivCongrLeft'`. 3. Add `…of lemma` for `sigmaCurry`, i.e. `sigmaCurry_of`. 4. Add `sigmaFiberAddEquiv`: the equivalence between a direct sum indexed by a type `ι₁` and the double sum indexed by a type `ι₂` and the fibres of a map `f : ι₁ → ι₂`. Add two `…_apply` lemmas and an `…_of` lemma. --- This is supposed to be a first step towards merging the draft PR #39356. re 1: Mathematically, I don't see why one version should be preferred over the other, but I found the existing `equivCongrLeft` more difficult to work with when the equivalence `h : ι ≃ κ` is naturally given in the opposite direction. (I could not avoid explicit type casts through the equality `h.symm.symm = h` when defining `sigmaFiberAddEquiv` in terms of `equivCongrLeft`.) Very unsure about the name of `equivCongrLeft'`. (I see that the name `equivCongrLeft` was chosen in analogy with `Equiv.piCongrLeft`. `Equiv.piCongrRight` looks very different, so presumably `equivCongrLeft'` should not be called `equivCongrRight`.) re 4: Very unsure about the naming of the two different `…_apply` lemmas; called them `…_apply` and `…_apply'` for now. The second (`…_apply'`) cannot be a `simp` lemma as it would prevent the first (`…_apply`) from firing. I've used Claude Opus for understanding error messages and git interaction, but everything is hand coded. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor label:t-algebra$	66/1	Mathlib/Algebra/DirectSum/Basic.lean	1	3	['github-actions']	nobody	13-2238 13 days ago	13-12971 13 days ago	13-12721 13 days
39236	quantumsnow author:quantumsnow	feat(AlgebraicTopology): `HomologyPretheory` for Eilenberg-Steenrod homology	This splits out a part of #38369 into a separate PR. It includes a structure `TopPair.HomologyPretheory` containing the data for an Eilenberg-Steenrod homology theory and the first Eilenberg-Steenrod axiom as a typeclass `EilenbergSteenrod.IsHomotopyInvariant`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebraic-topology new-contributor maintainer-merge awaiting-author	155/0	Mathlib.lean,Mathlib/AlgebraicTopology/EilenbergSteenrod.lean	2	37	['chrisflav', 'dagurtomas', 'github-actions', 'joelriou', 'quantumsnow']	robin-carlier assignee:robin-carlier	12-82163 12 days ago	12-82163 12 days ago	2-47026 2 days
33714	idontgetoutmuch author:idontgetoutmuch	feat(Mathlib/Geometry/Manifold): Riemannian metrics exist II	Supersedes https://github.com/leanprover-community/mathlib4/pull/33519 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-differential-geometry new-contributor	723/0	Mathlib.lean,Mathlib/Algebra/BigOperators/Finprod.lean,Mathlib/Geometry/Manifold/ExistsRiemannianMetric.lean,Mathlib/Geometry/Manifold/PartitionOfUnity.lean	4	200	['Rida-Hamadani', 'github-actions', 'grunweg', 'idontgetoutmuch']	nobody	12-50147 12 days ago	44-2639 44 days ago	89-9372 89 days
39474	emlis42 author:emlis42	feat(Topology/Separation/Hausdorff): add `Filter.limUnder_congr`	This PR adds `Filter.limUnder_congr` and some lemmas about `limUnder`. `Filter.limUnder_congr` allows rewriting `limUnder` expressions using equivalences of convergence behavior, without proving the filters actually converge, allowing convergence proofs to be carried out on more convenient expressions latter.	t-topology new-contributor large-import	24/1	Mathlib/Order/Filter/AtTopBot/Archimedean.lean,Mathlib/Topology/Separation/Hausdorff.lean	2	2	['github-actions']	PatrickMassot assignee:PatrickMassot	12-48559 12 days ago	16-68104 16 days ago	16-67854 16 days
35504	JoaBjo author:JoaBjo	feat(Probability/Distributions/Exponential): add MGF, moments, and memoryless property	feat(Probability/Distributions/Exponential): add MGF, moments, and memoryless property Add the main analytic results for the exponential distribution: - moment-generating function `mgf id (expMeasure r) t = r / (r - t)` for `t < r` - mean `∫ x, x ∂(expMeasure r) = r⁻¹` - variance `Var[id; expMeasure r] = r⁻¹ ^ 2` - `ℒp` membership for all `p` - tail probability `P(X > x) = exp (-(r * x))` - memoryless property `P(X > s + t \| X > s) = P(X > t)` The MGF is computed by reducing to the known improper integral `∫ exp(c * x)` on `Ioi`, and integrability is deduced by contradiction from the positive closed-form value. The mean and variance are computed via the Gamma function integral `∫₀^∞ x^(n-1) exp(-r x) dx = Γ(n) / rⁿ`. The memoryless property follows from the exponential identity `exp(-(r(s+t))) = exp(-rt) * exp(-rs)`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-measure-probability awaiting-author	200/0	Mathlib/Probability/Distributions/Exponential.lean	1	7	['EtienneC30', 'JoaBjo', 'Timeroot', 'github-actions']	EtienneC30 assignee:EtienneC30	12-2003 12 days ago	12-2004 12 days ago	42-8018 42 days
39192	jayscambler author:jayscambler	feat(InnerProductSpace/PiL2): det of a linear isometry has unit norm	Adds `LinearIsometryEquiv.norm_det` and the real corollary `LinearIsometryEquiv.abs_det`. The proof uses the unitary matrix of a linear isometry in orthonormal bases, via `LinearIsometryEquiv.toMatrix_mem_unitaryGroup` and `Matrix.det_of_mem_unitary`. The supporting matrix lemma is moved from `Adjoint.lean` to `PiL2.lean`, where it no longer depends on adjoints.	t-analysis new-contributor LLM-generated awaiting-author	36/10	Mathlib/Analysis/InnerProductSpace/Adjoint.lean,Mathlib/Analysis/InnerProductSpace/PiL2.lean	2	8	['github-actions', 'grunweg', 'jayscambler', 'sgouezel', 'themathqueen', 'wwylele']	sgouezel assignee:sgouezel	12-1480 12 days ago	12-1480 12 days ago	9-74648 9 days
39586	thomaskwaring author:thomaskwaring	feat: GraphLike typeclass	A proposal for a typeclass representing `GraphLike` objects. This is axiomatised in terms of a relations `IsSource` and `IsTarget` between edges and vertices, as well as `IsLink` to represent walks of length one. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	539/0	Mathlib/Combinatorics/GraphLike/Basic.lean,Mathlib/Combinatorics/GraphLike/Walk.lean	2	4	['SnirBroshi', 'eric-wieser', 'github-actions']	nobody	11-85749 11 days ago	unknown	unknown
38319	Zetetic-Dhruv author:Zetetic-Dhruv	feat(Combinatorics/SetFamily): Assouad's dual VC bound	Adds the Finset-level form of Assouad's 1983 dual VC bound: if a family `𝒜 : Finset (Finset α)` has VC dimension at most `d`, then for any ground set `X : Finset α` the dual family `{𝒜.filter (· ∋ x) : x ∈ X}` has VC dimension at most `2 ^ (d + 1) - 1`. New declarations (in `Finset` namespace): - `dualFamily 𝒜 X`: for each `x ∈ X`, the subfamily `{A ∈ 𝒜 \| x ∈ A}` - `mem_dualFamily` (`@[simp]`): membership characterisation - `exists_shatters_of_dualFamily_shatters`: Assouad's bitstring-coding lemma - `vcDim_dualFamily_le`: the headline VC bound Proof by Assouad's classical bitstring-coding argument. Sits on top of `Finset.shatterer` / `Finset.vcDim` from `Mathlib.Combinatorics.SetFamily.Shatter`. References: - P. Assouad, Densite et dimension, Ann. Inst. Fourier 33(3) (1983), Thm 2.13 - J. Matousek, Lectures on Discrete Geometry, GTM 212, Springer, 2002, Section 10.3 Lemma 10.3.3 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	199/0	Mathlib.lean,Mathlib/Combinatorics/SetFamily/DualVC.lean,docs/references.bib	3	37	['Shreyas4991', 'YaelDillies', 'Zetetic-Dhruv', 'github-actions']	nobody	11-80534 11 days ago	22-19428 22 days ago	40-14872 40 days
36667	NoneMore author:NoneMore	feat(ModelTheory): add `exClosure` definition for first-order formulas	Prepare for moving realizations between elementarily equivalent structures. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-logic	37/0	Mathlib/ModelTheory/Semantics.lean,Mathlib/ModelTheory/Syntax.lean	2	2	['github-actions']	nobody	11-50146 11 days ago	47-21683 47 days ago	79-31928 79 days
39673	drocta author:drocta	feat: add instances of MetricSpace, NormedAddGroup, and NormedAddCommGroup for DirectLimit	add files `Topology/MetricSpace/DirectLimit.lean` (with an instance of `MetricSpace` for a `DirectLimit` of a directed system of `MetricSpace`s with `IsometryClass` map types between them) and `Analysis/Normed/Group/DirectLimit.lean` (with instances of `NormedAddGroup` and `NormedAddCommGroup` on `DirectLimit`) also lemmas `dist_def` and `norm_def` for these. --- This PR is part of a project of adding support for direct limits of $C^*$-algebras (as I described [on Zulip](https://leanprover.zulipchat.com/#narrow/channel/113489-new-members/topic/Early.20feedback.20on.20approach.20towards.20formalizing.20UHF.20algebras.3F) ). This PR uses `IsometryClass` to implement the requirement that the directed systems preserve the `Norm` on the `NormedAddGroup`s, following the advice I got [this Zulip thread](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Representing.20norm-preservation.20for.20directed.20systems.3F/with/595941824) . Use of AI: I again used ChatGPT a bit for some advice when writing this (for example, for ideas for simplifying parts of proofs that I suspected could be simpler/shorter, and for advice on which of a couple options would be more idiomatic). I can personally vouch for all of these contributions, and that I understand this code.	t-topology new-contributor awaiting-author	258/0	Mathlib.lean,Mathlib/Analysis/Normed/Group/DirectLimit.lean,Mathlib/Analysis/Normed/Ring/DirectLimit.lean,Mathlib/Topology/MetricSpace/DirectLimit.lean	4	23	['drocta', 'eric-wieser', 'github-actions', 'j-loreaux']	nobody	11-32978 11 days ago	11-46448 11 days ago	0-13565 3 hours
39356	TentativeConvert author:TentativeConvert	pushforward of gradings along map between indexing sets	Pushforward of grading along map between indexing sets The main result of #36501 is that the quotient of a graded algebra by a homogeneous relation inherits a grading. This draft complements #36501 with the result that the grading on a graded algebra can be changed by "pushing forward" along an additive map of additive monoids. For example, an ℕ-grading can be turned into a ℤ-grading by pushing forward along the inclusion ℕ → ℤ, or collapsed to an even/odd-grading by pushing forward along the projection ℤ → ZMod 2. This result is currently in [`RingTheory/GradedAlgebra/Map/DecompositionMap_SetLike.lean`](https://github.com/TentativeConvert/mathlib4/blob/f4e54e0ec25f44c5d373e355e9926481e3102ccd/Mathlib/RingTheory/GradedAlgebra/Map/DecompositionMap_SetLike.lean). The changes to [`Mathlib/LinearAlgebra/CliffordAlgebra/Grading.lean`](https://github.com/TentativeConvert/mathlib4/blob/f4e54e0ec25f44c5d373e355e9926481e3102ccd/Mathlib/LinearAlgebra/CliffordAlgebra/Grading.lean) illustrate how the two results can be combined to give a new construction of the grading on the Clifford algebra: First, the grading on the tensor algebra is collapsed to an even/odd grading. With respect to this grading, the Clifford relation is homogeneous. The Clifford algebra is the quotient of the tensor algebra by the Clifford relation, so we obtain an induced grading on the Clifford algebra. Notes: This draft includes all of #36501, as this is necessary to demonstrate the application to Clifford algebras. Most of the changes shown below are from that PR. (I don't know how to include that PR and highlight only the changes made on top of it here.) --- - [ ] depends on: #36501 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebraic-geometry new-contributor blocked-by-other-PR merge-conflict	1303/46	Mathlib.lean,Mathlib/Algebra/BigOperators/Group/Finset/Basic.lean,Mathlib/Algebra/DirectSum/Decomposition.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Basic.lean,Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Scheme.lean,Mathlib/Data/DFinsupp/BigOperators.lean,Mathlib/LinearAlgebra/CliffordAlgebra/Conjugation.lean,Mathlib/LinearAlgebra/CliffordAlgebra/EvenEquiv.lean,Mathlib/LinearAlgebra/CliffordAlgebra/Grading.lean,Mathlib/LinearAlgebra/CliffordAlgebra/Prod.lean,Mathlib/LinearAlgebra/TensorAlgebra/Grading.lean,Mathlib/RingTheory/GradedAlgebra/Basic.lean,Mathlib/RingTheory/GradedAlgebra/Homogeneous/Ideal.lean,Mathlib/RingTheory/GradedAlgebra/Homogeneous/RingQuot.lean,Mathlib/RingTheory/GradedAlgebra/HomogeneousLocalization.lean,Mathlib/RingTheory/GradedAlgebra/Map/AddSubmonoidSSup.lean,Mathlib/RingTheory/GradedAlgebra/Map/DecompositionMap_SetLike.lean,Mathlib/RingTheory/GradedAlgebra/Map/Tests.lean,Mathlib/RingTheory/GradedAlgebra/Map/auxiliary.lean,Mathlib/RingTheory/GradedAlgebra/Map/locations.md,Mathlib/RingTheory/GradedAlgebra/Map/order-preserving-maps.md,Mathlib/RingTheory/Ideal/Span.lean	22	4	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	11-24239 11 days ago	unknown	unknown
39687	TentativeConvert author:TentativeConvert	feat(Algebra/Group/Submonoid): type class to indicate that supremum in a SubmonoidClass agrees with supremum of submonoids	Add a type class `SubmonoidClass.IsConcreteSSup` to indicate that the canonical map `.ofClass` from a class `S` of submonoids of `M` to `Submonoid M` preserves suprema. --- This PR implements the minimal type class assumption needed to make „pushfoward of gradings along maps of indexing sets“ – see draft PR #39356 – work in some `SetLike` generality. Given `{S M : Type} [SetLike S M] [Monoid M] [SubmonoidClass S M]`, we have canonical maps ``` S → Submonoid M → Set M ``` The first is `Submonoid.ofClass`, the second and the composition are `coe` maps coming from the `SetLike` structures. Depending on `S`, these maps may or may not satisfy various properties with respect the lattice structures on `Submonoid M` and `Set M`. Mathlib so far includes the type class `[IsConcreteLE S M]`, which asserts that the composition `S → Set M` is order-preserving and order-reflecting. The type class defined here asserts that the first map, `S → Submonoid M`, preserves suprema. In examples such as `S = Subgroup M`, `S = Submodule R M`, much more is true – in these cases, `S` is a complete sublattice of `Submonoid M`. But there are also examples where only the weaker property defined here holds, e.g. `S = OpenSubgroup M` for a topological group `M`. Note on `outParam`: I did not* write `(M : outParam Type)` in the assumptions of `SubmonoidClass.IsConcreteSSup` in accordance with the [DocString of `Setlike`](https://leanprover-community.github.io/mathlib4_docs/Mathlib/Data/SetLike/Basic.html#SetLike). However, we do have `(B : outParam Type)` in the definition of `IsConcreteLE`, so perhaps I'm misinterpreting the DocString. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-algebra label:t-algebra$	56/0	Mathlib.lean,Mathlib/Algebra/Group/Submonoid/SSup.lean	2	2	['github-actions']	nobody	11-18540 11 days ago	11-17904 11 days ago	11-17654 11 days
39589	ScottWe author:ScottWe	feat: simple lemmas about Hermitian matrices	This pull request establishes some simple proofs about Hermitian algebras. In particular: - Unitary Hermitian matrices are self-inverse; - Hermitian matrices are in correspondence with skew-adjoint matrices.	new-contributor awaiting-author t-algebra t-analysis label:t-algebra$	72/0	Mathlib.lean,Mathlib/Analysis/Matrix/SkewAdjoint.lean,Mathlib/LinearAlgebra/Matrix/Hermitian.lean,Mathlib/LinearAlgebra/Matrix/Unitary.lean	4	13	['ScottWe', 'SnirBroshi', 'github-actions', 'j-loreaux', 'themathqueen']	nobody	11-1563 11 days ago	13-63245 13 days ago	0-7106 1 hour
37718	SabrinaJewson author:SabrinaJewson	feat(Order): add conversions from `Std` order typeclasses to Mathlib ones	`{Preorder, PartialOrder, LinearOrder}.ofStd` exist to facilitate convenient translation from `Std` order typeclasses to Mathlib ones. The design is modelled closely after [`Init.Data.Order.PackageFactories`](https://leanprover-community.github.io/mathlib4_docs/Init/Data/Order/PackageFactories.html) (`Std.PreorderPackage` is equivalent-ish to Mathlib’s `Preorder`, and same for partial and linear orders). The `OfStdArgs` types allow conveniently bundling a whole bunch of default arguments together in a way that allows one default argument set to `extends` another. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-order new-contributor maintainer-merge	391/0	Mathlib.lean,Mathlib/Order/Std.lean,MathlibTest/OrderOfStd.lean	3	9	['SabrinaJewson', 'YaelDillies', 'github-actions']	YaelDillies assignee:YaelDillies	10-65257 10 days ago	10-75361 10 days ago	56-47963 56 days
39697	sorrachai author:sorrachai	feat(Data/Tree/Basic): add Membership instance, new notation, rename Tree	Summary: 1. [Rename]([#CSLib > Splay tree PR: BinaryTree vs Tree @ 💬](https://leanprover.zulipchat.com/#narrow/channel/513188-CSLib/topic/Splay.20tree.20PR.3A.20BinaryTree.20vs.20Tree/near/596482765)) from Tree to BinaryTree, which propagates the changes to other files that use it. 2. Add membership instance, prove decidability of membership. 3. Add toListInOrder, toListPreOrder, toListPostOrder Suggestion based on the discussion in the cslib [thread](https://leanprover.zulipchat.com/#narrow/channel/513188-CSLib/topic/Splay.20tree.20PR/near/596568391)[#CSLib > Splay tree PR @ 💬](https://leanprover.zulipchat.com/#narrow/channel/513188-CSLib/topic/Splay.20tree.20PR/near/596568391). --- * depends on: #39707	new-contributor	187/75	Mathlib/Combinatorics/Enumerative/Catalan/Tree.lean,Mathlib/Combinatorics/Enumerative/DyckWord.lean,Mathlib/Data/Tree/Basic.lean,Mathlib/Data/Tree/Get.lean,Mathlib/Data/Tree/Traversable.lean,Mathlib/Tactic/CancelDenoms/Core.lean,docs/overview.yaml	7	4	['eric-wieser', 'github-actions', 'sorrachai']	nobody	10-58272 10 days ago	11-2717 11 days ago	11-2467 11 days
35069	A-M-Berns author:A-M-Berns	feat(Geometry/Polygon): simple polygons and boundary map	This PR introduces Simple polygons with the predicate `IsSimple`, which captures the idea of a non-self-intersecting boundary, in the file Simple.lean. In the file Boundary.lean, a boundary map from `AddCircle n` is defined. I prove that the range of this map is the boundary and that this map is injective if and only if the polygon is simple. I kept Boundary.lean and Simple.lean separate because future results will include stuff just about the boundary map independent of simplicity (e.g. that it is continuous in the appropriate setting) and stuff just about simple polygons independent of the boundary map (e.g. that for n = 3, IsSimple iff HasNondegenerateVertices.) I used Claude Code to help generate some of the proof material, but I golfed and edited all AI contribution. - [x] depends on: #34598 ---	new-contributor t-euclidean-geometry LLM-generated	360/0	Mathlib.lean,Mathlib/Geometry/Polygon/Boundary.lean,Mathlib/Geometry/Polygon/Simple.lean,Mathlib/Logic/Equiv/Fin/Rotate.lean	4	30	['A-M-Berns', 'eric-wieser', 'github-actions', 'joneugster', 'jsm28', 'mathlib-dependent-issues', 'mathlib-merge-conflicts', 'vihdzp', 'wwylele']	nobody	10-50149 10 days ago	96-68664 96 days ago	99-17409 99 days
35402	samueloettl author:samueloettl	feat(Dynamics/BirkhoffSum): birkhoffAverage const	--- I think this is useful and one of these should be a simp lemma. I'm not really sure if I got the naming of the theorems correct. When generalizing to the assumption (n : R) ≠ 0 instead of the special case CharZero R with n ≠ 0 I had to use "open Classical in". I'm a bit unfamiliar with that part so please check if this makes sense. See also https://github.com/leanprover-community/mathlib4/pull/35307#discussion_r2823586252 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-dynamics new-contributor	14/0	Mathlib/Dynamics/BirkhoffSum/Average.lean	1	26	['Maldooor', 'github-actions', 'lua-vr', 'mcdoll', 'samueloettl']	sgouezel assignee:sgouezel	10-48975 10 days ago	29-2208 29 days ago	99-82756 99 days
39518	abeldonate author:abeldonate	feat(RingTheory/LocalProperties/Projective): Projective Module theorem	Theorem: R Noetherian, M finitely generated R-Mod. Then: M projective iff M_m free for all m maximal	t-ring-theory new-contributor large-import	21/0	Mathlib/RingTheory/LocalProperties/Projective.lean	1	9	['abeldonate', 'github-actions', 'mbkybky', 'vlad902']	nobody	10-24664 10 days ago	10-24012 10 days ago	14-42206 14 days
39735	allenhaozhu author:allenhaozhu	feat(LinearAlgebra/Matrix): regularized inverse limit and trace continuity	Add `Matrix.regularizedInv_mul_tendsto_one` and the trace corollaries `Matrix.trace_regularizedInv_mul_tendsto` and `Matrix.trace_regularizedInv_mul_tendsto_card`: for a square matrix `M` over a normed field with `det M ≠ 0`, the Tikhonov-regularized expression `(M + lam • 1)⁻¹ * M` tends to the identity matrix as the scalar `lam` tends to zero, and consequently its trace tends to `tr 1 = (Fintype.card d : R)`. The proofs compose `NormedRing.inverse_continuousAt`, `continuousAt_matrix_inv`, `Matrix.nonsing_inv_mul`, and `Continuous.matrix_trace`; no new definitions are added. These lemmas are useful in matrix-regularization limit arguments arising in numerical linear algebra (Tikhonov-regularized least squares, ridge regression) and in statistics. --- ## AI-assistance disclosure Per the Mathlib [AI-use policy](https://leanprover-community.github.io/contribute/index.html#use-of-ai): - Tool. Claude Code (Anthropic) with the Claude Sonnet 4.6 model. - Use. I specified the target lemma statements and the proof strategy; the assistant drafted Lean 4 tactic combinations against current Mathlib. I iterated on the proofs, verified each lemma builds under `lake build` from a clean checkout, and read the final code. - Vouching. I have read every declaration in this file and can defend the proofs without further AI assistance. I welcome reviewer feedback on naming, namespace placement, and stylistic alignment with the surrounding Mathlib modules.	t-algebra new-contributor LLM-generated label:t-algebra$	109/0	Mathlib.lean,Mathlib/LinearAlgebra/Matrix/InverseLimit.lean	2	2	['github-actions']	nobody	10-24494 10 days ago	unknown	unknown
39734	allenhaozhu author:allenhaozhu	feat(Analysis/CStarAlgebra/CStarMatrix): operator-monotone rpow/log/sqrt specializations	Adds three discoverability lemmas for operator-monotonicity on `CStarMatrix n n A`, specializing the existing C\-algebra-level results from `CFC.monotone_rpow` / `CFC.log_monotoneOn` / `CFC.monotone_sqrt`: ``` CStarMatrix.monotone_rpow {p : ℝ} (hp : p ∈ Set.Icc 0 1) : Monotone (fun M : CStarMatrix n n A => M ^ p) CStarMatrix.log_monotoneOn : MonotoneOn (CFC.log : CStarMatrix n n A → CStarMatrix n n A) {M \| IsStrictlyPositive M} CStarMatrix.monotone_sqrt : Monotone (CFC.sqrt : CStarMatrix n n A → CStarMatrix n n A) ``` In the course of implementing these specializations, three shortcut instances are also registered to bypass a typeclass-diamond issue. `CStarMatrix n n A` derives `CStarAlgebra` from the underlying `CStarAlgebra A`, but the typeclass search for `ContinuousFunctionalCalculus ℝ (CStarMatrix n n A) IsSelfAdjoint` does not find the path through the `Matrix` diamond automatically. Explicit shortcut instances enable ergonomic use of `CFC.rpow`, `CFC.log`, etc.: ``` instance instContinuousFunctionalCalculusRealIsSelfAdjoint instance instNonUnitalContinuousFunctionalCalculusRealIsSelfAdjoint instance instNonnegSpectrumClassReal ``` Reviewer note:* I am NOT attached to this PR — if reviewers prefer that downstream users call `CFC.monotone_rpow` directly and accept the typeclass-search cost, please close. The PR is offered as a convenience on the assumption that matrix-shaped users may search the matrix namespace first and benefit from the diamond shortcut. The shortcut instances may also belong in a separate PR if reviewers prefer. Extracted from LTFP-Lean (mechanical formalization of Bach's Learning Theory from First Principles), where matrix-side ergonomics matter for downstream proofs. --- ## AI-assistance disclosure Per the Mathlib [AI-use policy](https://leanprover-community.github.io/contribute/index.html#use-of-ai): - Tool. Claude Code (Anthropic) with the Claude Opus 4.7 model. - Use. I specified the three target specialization lemmas. The assistant placed them in the right file, discovered the typeclass-diamond issue while implementing (adding 3 shortcut instances to resolve it), drafted the proofs, and verified the build under `lake build Mathlib.Analysis.CStarAlgebra.CStarMatrix.OperatorMonotone`. I reviewed the final code. - Vouching. I have read the declarations and can defend the proofs without further AI assistance. I welcome reviewer feedback on: - whether the three specialization lemmas justify their own file or should be merged into `CStarMatrix.lean` - whether the typeclass-diamond shortcut instances belong in this PR or a separate one - whether the convenience-layer is justified at all vs. having downstream users call `CFC.*` directly	t-analysis new-contributor LLM-generated	101/0	Mathlib.lean,Mathlib/Analysis/CStarAlgebra/CStarMatrix/OperatorMonotone.lean	2	2	['github-actions']	nobody	10-24464 10 days ago	unknown	unknown
39733	allenhaozhu author:allenhaozhu	feat(LinearAlgebra/Matrix): nonsingular inverse commutes with any monoid hom of matrix rings	Adds `Matrix.map_nonsing_inv`: for any `MonoidHomClass` morphism `f : Matrix n n R →* Matrix n n S` between matrix rings over commutative rings, and any `A : Matrix n n R` with `IsUnit A.det`, ``` (f A)⁻¹ = f A⁻¹ ``` The proof is short: `Matrix.inv_eq_right_inv` plus the fact that `f` preserves `` and `1`: ```lean theorem map_nonsing_inv (f : F) {A : Matrix n n R} (hA : IsUnit A.det) : (f A)⁻¹ = f A⁻¹ := by apply Matrix.inv_eq_right_inv rw [← map_mul, Matrix.mul_nonsing_inv A hA, map_one] ``` Since `RingHom`, `RingEquiv`, `AlgHom`, `AlgEquiv`, and `StarAlgEquiv` between matrix rings all provide `MonoidHomClass` instances, the lemma applies uniformly to all of them — in particular to `Unitary.conjStarAlgAut`-style conjugations by a unitary matrix, which is the original motivating use case. This came up in a downstream project (mechanical formalization of Bach's Learning Theory from First Principles), where it underpins a spectral-identity proof: `(U X * star U)⁻¹ = U * X⁻¹ * star U` for unitary `U` and invertible `X`. Rather than special-case the unitary-conjugation version, I generalized to any `MonoidHomClass` since the proof works mechanically. ### Why not just `map_inv`? The generic `map_inv` discharges `⁻¹` through a `MonoidHom` between groups, but `Matrix n n R` is not a group under multiplication — `⁻¹` here is `Matrix.nonsing_inv` (adjugate / det), which is only a two-sided inverse on the submonoid of nonsingular matrices. So `map_inv` doesn't apply directly; we need the `IsUnit A.det` hypothesis and a custom proof routed through `Matrix.inv_eq_right_inv`. ### Tests - `lake build Mathlib.LinearAlgebra.Matrix.NonsingularInverse` — green - `lake build Mathlib.Analysis.Matrix.Spectrum Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Defs` — green (downstream smoke check, no regressions) - Verified usability against both `RingEquiv` and `StarAlgEquiv` instances via local smoke tests ### Notes on AI assistance Per the Mathlib [AI-use policy](https://leanprover-community.github.io/contribute/index.html#use-of-ai): - Tool. Claude Code (Anthropic), Claude Opus 4.7 model. - Use. I specified the target statement (originally `ℝ`-specific to a unitary conjugation) and the scope of generalization. The assistant drafted the more general `MonoidHomClass` version, chose the file home, verified the proof builds under `lake build`, and tested downstream files for regressions. I reviewed the proof, naming, and file placement. - Vouching. I have read the declaration and can defend the proof without further AI assistance. Happy to take reviewer feedback on naming (`map_nonsing_inv` vs alternatives), namespace placement, or whether the typeclass bound should be relaxed further (e.g. to `MulHomClass` if we can avoid `map_one` — though `map_mul` + `mul_nonsing_inv = 1` + applying `f` to `1` seems to genuinely require `OneHomClass` too).	t-algebra new-contributor LLM-generated label:t-algebra$	17/0	Mathlib/LinearAlgebra/Matrix/NonsingularInverse.lean	1	2	['github-actions']	nobody	10-24447 10 days ago	unknown	unknown
39718	RaggedR author:RaggedR	feat(Archive): dual Langer graph and GH(2,2) non-self-duality	This PR introduces the dual Langer graph, the line-collinearity graph of the split Cayley hexagon GH(2,2), and establishes the algebraic infrastructure for proving that it is not isomorphic to the Langer graph (the point-collinearity graph). Both graphs share the intersection array {6, 4, 4; 1, 1, 3} but are distinguished by the connectivity of their distance-3 subgraphs. The key mathematical contribution is deriving the G₂(2) line-action from the point-action (already in Archive.LangerGraph) via the triangle-line bijection. Each line of GH(2,2) corresponds to a unique triangle in the Langer graph, and the point-action sends triangles to triangles, inducing an action on lines. The induced line-action preserves the share-a-vertex relation, which is proved algebraically using Finset.image_inter (injective maps commute with intersection) and Finset.image_nonempty (images preserve non-emptiness). The equivariance of each generator is a 63-case native_decide verification, after which the word-level preservation follows by structural induction with no further computation. Two sorries remain. The bridge theorem connecting dual Langer adjacency to the share-vertex relation is a native_decide that needs tuning for the kernel recursion limit. The non-isomorphism theorem, which uses d₃-subgraph connectivity as a distinguishing invariant transported to all vertices via the line-action, depends on this bridge. These will be closed in a follow-up once the computational proofs are optimized. This PR depends on Archive.LangerGraph.	t-combinatorics new-contributor	7203/0	Archive.lean,Archive/BolzaSurface.lean,Archive/ClayworthGraph.lean,Archive/ClayworthSurface.lean,Archive/DualLangerGraph.lean,Archive/HeawoodSurface.lean,Archive/KleinSurface.lean,Archive/LangerGraph.lean,Archive/Meinhold1344.lean,Archive/Meinhold2016.lean,Archive/Meinhold504.lean,Archive/Meinhold576.lean,Archive/MeinholdGraphs.lean,Archive/PrimitiveGraphs.lean,Archive/TriangleGroupSurface.lean,Archive/VoltageGraphs.lean,Archive/ZhouGraph.lean,Mathlib.lean,Mathlib/Combinatorics/CellularSurface.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/SabidussiWitness.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	25	3	['github-actions', 'mathlib-bors']	nobody	10-14061 10 days ago	unknown	unknown
39698	RaggedR author:RaggedR	feat(Archive): Meinhold family — five Sabidussi coset graphs of G₂(2)	Five coset graphs of the exceptional Chevalley group G₂(2), each arising as Sab(G₂(2), K, D) for intermediate subgroups C₃ ≤ K ≤ G₂(2). The Clayworth graph (4032 vertices, cubic, genus 505) is the base case K = C₃. Meinhold-72 has 72 vertices, is 7-regular with girth 4, via K = PSL(3,2). Meinhold-504 has 504 vertices, is 24-regular with girth 4, via S₄. Meinhold-576 has 576 vertices, is 7-regular with girth 6, via C₇:C₃. Meinhold-1344 has 1344 vertices, is 9-regular with girth 6, via C₃×C₃. Meinhold-2016 has 2016 vertices, is 6-regular with girth 8, via C₆. Each graph has a Sabidussi isomorphism proving arc-transitivity, is connected, and has a shortest cycle witness establishing the girth. ![Meinhold-72](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/meinhold-72.jpeg) The Langer graph (63 vertices, 6-regular) is proved not to be a quotient of Clayworth: the three G₂(2)-invariant 63-block systems have quotient degrees 24, 32, 32, none of which equals 6. The Clayworth graph itself is proved to be a Sabidussi coset graph Sab(G₂(2), C₃, D) with two generators of orders 7 and 6 preserving adjacency, and BFS witness words establishing transitivity. The current approach is admittedly brute-force — the Clayworth graph is defined via a flat adjacency array and the quotient maps are verified by native_decide on concrete vertex data. A more algebraic treatment, deriving the Meinhold graphs directly from the coset lattice of G₂(2) without storing explicit adjacency data, would be cleaner and is planned as a follow-up. These graphs arise from my honours thesis on symmetric graph quotients (arXiv:1306.4798). The Meinhold family is named after Nick Meinhold, co-founder of Imagineering Melbourne. Depends on #39654 (CellularSurface instances, Clayworth graph). --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics LLM-generated new-contributor	6884/0	Archive.lean,Archive/BolzaSurface.lean,Archive/ClayworthGraph.lean,Archive/ClayworthSurface.lean,Archive/HeawoodSurface.lean,Archive/KleinSurface.lean,Archive/LangerGraph.lean,Archive/Meinhold1344.lean,Archive/Meinhold2016.lean,Archive/Meinhold504.lean,Archive/Meinhold576.lean,Archive/MeinholdGraphs.lean,Archive/PrimitiveGraphs.lean,Archive/TriangleGroupSurface.lean,Archive/VoltageGraphs.lean,Archive/ZhouGraph.lean,Mathlib.lean,Mathlib/Combinatorics/CellularSurface.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/SabidussiWitness.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	24	4	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14060 10 days ago	unknown	unknown
39695	RaggedR author:RaggedR	feat(Archive): Zhou-3 arc-transitivity and Lorimer quotient to Zhou-6	The Zhou-3 graph (Foster census F182A, 182 vertices, cubic) has an imprimitive block system of 91 blocks of size 2. This PR proves the block system is invariant under the full PSL(2,13) action via closure induction on the generators, with a pigeonhole argument for the inverse case. The setwise stabilizer of the block containing vertex 0 is D₁₂ (dihedral of order 12), which contains the point stabilizer S₃ at index 2. With the block structure established, Lorimer's quotient theorem (from #39551) is instantiated for the first time on a concrete graph: the quotient of Sab(PSL(2,13), S₃, D) by D₁₂ is isomorphic to Sab(PSL(2,13), D₁₂, D₁₂·D·D₁₂). The two hypotheses — H ≤ K and D ∩ K = ∅ — are verified, the first using the closure block invariance theorem and the second by observing that any element of K maps vertex 0 into {0, 137}, but neither is a neighbor of 0. Arc-transitivity of Zhou-3 is proved via Lorimer's forward theorem: the connection set is a single double coset S₃·a·S₃ where a is an explicit involution (a word of length 9 in the generators) that swaps vertex 0 with its neighbor 3. ![Zhou-3 graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/zhou3-F182A.jpg) ![Zhou-6 graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/zhou6-91v.jpg) This depends on the Sabidussi/Lorimer chain (#39530, #39548, #39550, #39551) and on #39654 for the Zhou-3 Sabidussi representation and SabidussiWitness infrastructure.	t-combinatorics new-contributor LLM-generated	8575/0	Archive.lean,Archive/BolzaSurface.lean,Archive/ClayworthSabidussi.lean,Archive/ClayworthSurface.lean,Archive/HeawoodSurface.lean,Archive/KleinSurface.lean,Archive/VoltageGraphs.lean,Archive/ZhouGraph.lean,Mathlib.lean,Mathlib/Combinatorics/CellularSurface.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/SabidussiWitness.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	16	3	['github-actions', 'mathlib-bors']	nobody	10-14059 10 days ago	unknown	unknown
39654	RaggedR author:RaggedR	feat(Archive): CellularSurface instances (genus 1, 2, 3, 505)	This PR provides concrete CellularSurface instances for the four CSS surface codes: Heawood (genus 1), Bolza (genus 2), Klein quartic (genus 3), and Clayworth (genus 505). Each surface embeds a cubic arc-transitive graph arising from a Sabidussi coset construction, and the chain complex d1, d2 satisfies the boundary condition d1 · d2 = 0 that gives the CSS orthogonality. Together with #39653, which proves that k = 2g for any surface tiling, these instances yield formally verified CSS codes with parameters [[21, 2]], [[24, 4]], [[84, 6]], and [[6048, 1010]] respectively. The Heawood and Bolza surfaces are small enough that all axioms are verified by decide. Both include bridge theorems proving the CellularSurface graph matches the corresponding voltage graph on K₂ from VoltageGraphs.lean. The Klein quartic embeds the Klein graph (56 vertices) from the triangle group Δ(2,3,7) acting on PSL(2,7), with a Sabidussi proof. The Clayworth surface is the interesting case: 4032 vertices, 6048 edges, 1008 dodecagonal faces, genus 505. Rather than storing tens of thousands of array entries, the construction works algebraically from the regular representation of G₂(2) on 12096 darts, using a general TriangleGroupSurface module that derives a CellularSurface from any finite quotient of Δ(2,3,r). The key identity is that T = RS implies the far endpoint of each dart has the same vertex as its R-successor, because S preserves vertex cosets. There are five sorrys. Four are dual graph regularity theorems (Heawood 6-regular, Bolza 8-regular, Klein 7-regular, Clayworth 12-regular), all of which should be closable by native_decide. The fifth is the Clayworth Sabidussi isomorphism, where the individual native_decide checks all pass but the kernel struggles to assemble the SabidussiWitness structure for 4032 vertices. These are left for a follow-up. ![Klein graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/klein-F056A.jpg) ![Zhou-3 graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/zhou3-F182A.jpg) ![Zhou-6 graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/zhou6-91v.jpg) Depends on #39653 (CellularSurface, k = 2g). Cross-references #39649 (Langer/G₂(2) ecosystem), #39651 (voltage graphs).	t-combinatorics new-contributor LLM-generated	2390/0	Archive.lean,Archive/BolzaSurface.lean,Archive/ClayworthSurface.lean,Archive/HeawoodSurface.lean,Archive/KleinSurface.lean,Archive/TriangleGroupSurface.lean,Archive/VoltageGraphs.lean,Mathlib.lean,Mathlib/Combinatorics/CellularSurface.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/SabidussiWitness.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	15	9	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14058 10 days ago	11-48025 11 days ago	0-39438 10 hours
39653	RaggedR author:RaggedR	feat(Combinatorics): cellular surfaces, CSS quantum codes, and k = 2g	This formalises CSS quantum error-correcting codes from surface tilings, following Breuckmann & Terhal (arXiv:1506.04029). CellularSurface encodes the combinatorial data of a 2-cell embedding of a graph on a closed surface: vertices, edges with endpoints, and faces whose boundaries are closed directed trails. The boundary operators ∂₁ (vertex-edge incidence) and ∂₂ (edge-face boundary) are matrices over F₂. The theorem `d1_mul_d2_eq_zero` proves ∂₁ ∘ ∂₂ = 0 (the chain complex condition) from the closed walk axiom: each vertex in a face boundary is visited an even number of times, so the sum vanishes in characteristic 2. The theorem `d1_rank_eq` proves rank(∂₁) = V − 1 for connected graphs — the kernel of ∂₁ᵀ is span{1} because elements of the kernel assign equal values to adjacent vertices, and connectivity propagates this to all vertices. The theorem `d2_rank_eq` proves rank(∂₂) = F − 1 for connected dual graphs with the two-sides condition (each edge borders exactly 2 faces). The main result `css_k_eq_2g` gives the number of logical qubits k = 2g. This is pure arithmetic: k = E − rank(∂₁) − rank(∂₂) = E − (V−1) − (F−1) = E − V − F + 2 = 2g by Euler's formula. No `native_decide` — all proofs are structural. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	1236/0	Mathlib.lean,Mathlib/Combinatorics/CellularSurface.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	7	7	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14056 10 days ago	10-14058 10 days ago	1-3116 1 day
39651	RaggedR author:RaggedR	feat(Archive): voltage graphs on K₂, Heawood and Möbius-Kantor graphs	This defines `voltageGraphK2`, a cubic covering construction on K₂ with cyclic voltage group `ZMod m`. Vertices are `Fin 2 × ZMod m`, with edges `(0, g) ~ (1, g + vⱼ)` for three voltages. Two instances are provided. The Heawood graph (F014A) is `voltageGraphK2 7 0 4 6`, the Levi graph of the Fano plane PG(2,2): 14 vertices, cubic, girth 6, equal to Sab(G₄₂, C₃) where G₄₂ = Z₇ ⋊ Z₆. The Möbius-Kantor graph (F016A) is `voltageGraphK2 8 0 1 3`, the generalised Petersen graph GP(8,3): 16 vertices, cubic, girth 6, equal to Sab(GL(2,3), C₃). Both quotient to K₂ under the fibre projection `Prod.fst`, recovering the base graph. ![Heawood graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/heawood-F014A.jpg) ![Möbius-Kantor graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/mobius-kantor-F016A.jpg) The voltage graph construction and named graph instances follow Langer, arXiv:1306.4798, and Gross & Tucker, Topological Graph Theory. Depends on #39551 (quotient graphs and Lorimer's theorem). --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	1113/0	Archive.lean,Archive/VoltageGraphs.lean,Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	8	6	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14055 10 days ago	10-14057 10 days ago	1-47361 1 day
39650	RaggedR author:RaggedR	feat(Archive): dodecahedron, Petersen graph, 3-cube, and antipodal quotients	This defines the dodecahedron graph (Fin 20, 3-regular, 30 edges), the Petersen graph (Fin 10, as the antipodal quotient of the dodecahedron), and the 3-cube Q₃ (Fin 8, 3-regular, 12 edges) with its antipodal quotient proved equal to K₄. The Petersen graph is defined as `dodecahedronGraph.quotientGraph dodecAntipodalMap`, using the quotient graph infrastructure from #39551. The antipodal involution on the dodecahedron identifies each vertex with the vertex at distance 5 (diametrically opposite). The 3-cube's antipodal involution (bitwise complement) quotients to K₄ = ⊤. ![Dodecahedron → Petersen quotient](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/dodecahedron-quotient-petersen.jpeg) ![Cube → K₄ quotient](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/cube-quotient-k4.jpeg) The graph definitions and quotient constructions follow Langer, arXiv:1306.4798. Depends on #39551 (quotient graphs and Lorimer's theorem). --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	1097/0	Archive.lean,Archive/NamedGraphs.lean,Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	8	8	['RaggedR', 'github-actions', 'mathlib-bors', 'vihdzp']	nobody	10-14054 10 days ago	10-14056 10 days ago	1-76973 1 day
39649	RaggedR author:RaggedR	feat(Archive): Langer graph, Tutte 12-cage, and structural equality via G₂(2)	This adds three constructions from the theory of generalized polygons over finite fields to Archive/, and proves they give the same graph using the Sabidussi representation theorem from #39548 and #39550. The Langer graph (63 vertices, 6-regular) is the collinearity graph of the split Cayley hexagon GH(2,2). It has three independent definitions: algebraically via the Zorn product on Q(6,2) (`langerSimpleGraph`), geometrically as the distance-2 graph of the Tutte 12-cage restricted to points (`tutte12Distance2Graph`), and group-theoretically as the coset graph Sab(G₂(2), H₁₉₂, D) where H₁₉₂ is the point stabiliser of order 192 (`langerCosetGraph`). The main result `langer_iso_tutte12_distance2` proves the algebraic and geometric definitions are isomorphic by composing two Sabidussi isos through a common coset graph. Both graphs are G₂(2)-invariant and arc-transitive, so `sabidussiIso` maps each to Sab(G₂(2), Stab(0), D). Since they have the same 6 neighbors at vertex 0, their connection sets are equal (`dist2_connectionSet_eq`), so both map to the same coset graph. The proof is `langerSabidussiIso.trans dist2SabidussiIso.symm`. ![Langer graph](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/langer-63v.jpg) ![Tutte 12-cage](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/tutte-12cage.jpg) Also included: the Tutte 12-cage (126 vertices, semisymmetric because GH(2,2) has no polarity over F₂), and self-orthogonality of the Q(6,2) parity-check matrix. Generator data was produced by `compute_g2_generators.py` in the source repo at RaggedR/symmetric-graphs. Depends on #39548 (coset graphs), #39550 (Sabidussi representation), #39551 (quotient graphs). The `sabidussiIso`, `connectionSet`, and `GraphAction` from those PRs are load-bearing in the equivalence proof. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	1576/0	Archive.lean,Archive/LangerGraph.lean,Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	8	8	['RaggedR', 'github-actions', 'mathlib-bors', 'wwylele']	nobody	10-14053 10 days ago	10-14054 10 days ago	1-51597 1 day
39636	RaggedR author:RaggedR	feat(RingTheory/HopfAlgebra): ascending Pochhammer is of binomial type	This adds two concrete examples to the delta operator framework from #39465, illustrating the change of basis between the two classical families of binomial-type sequences beyond the monomials. The first file proves that the ascending Pochhammer (rising factorial) sequence is of binomial type. The backward difference operator ∇f(x) = f(x) − f(x−1) is defined, shown to be a delta operator, and the ascending Pochhammer sequence is verified as its basic sequence via a telescoping argument. The final theorem `ascPochhammer_isBinomialType` is a one-line application of Rota's classification from #39465, complementing the existing `descPochhammer_isBasicSequence_forwardDiff` for falling factorials and the forward difference. The second file computes the Jabotinsky matrix entries of the geometric delta series y/(1−y), giving the unnormalized Lah numbers C(n−1, k−1) as the change-of-basis coefficients between rising and falling factorials. The proof factors the power (y/(1−y))ᵏ = Xᵏ · (1−X)⁻ᵏ and applies Mathlib's existing `mk_one_pow_eq_mk_choose_add` for the negative binomial series. --- - [ ] depends on: #39465 --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-ring-theory new-contributor blocked-by-other-PR LLM-generated	1596/0	Mathlib.lean,Mathlib/RingTheory/HopfAlgebra/AscPochhammer.lean,Mathlib/RingTheory/HopfAlgebra/BinomialType.lean,Mathlib/RingTheory/HopfAlgebra/DeltaOperator.lean,Mathlib/RingTheory/HopfAlgebra/Lah.lean,Mathlib/RingTheory/HopfAlgebra/Polynomial.lean	6	9	['RaggedR', 'github-actions', 'mathlib-bors', 'mathlib-dependent-issues', 'themathqueen']	nobody	10-14051 10 days ago	unknown	unknown
39551	RaggedR author:RaggedR	feat(Combinatorics/SimpleGraph): Lorimer's theorem and quotient graphs	This completes the algebraic theory of symmetric graphs by proving Lorimer's theorem (both directions) and the Lorimer quotient theorem, building on the Sabidussi representation theorem from #39550. Lorimer's theorem characterizes symmetric (arc-transitive) graphs in terms of coset graphs. The forward direction shows that Sab(G, H, HaH) is arc-transitive whenever a is an involution not in H. The proof establishes local transitivity at the identity coset by exploiting the double coset decomposition of neighbors, then transports it to all vertices by conjugation. The reverse direction shows that every arc-transitive graph's connection set is a single double coset GᵥaGᵥ, where a is the element swapping an arc (v, w). This a satisfies a ∉ Gᵥ and a² ∈ Gᵥ. The quotient theorem shows that the quotient of Sab(G, H, D) by an overgroup K ≥ H (with D ∩ K = ∅) is isomorphic to Sab(G, K, KDK) where KDK is the expanded connection set. The isomorphism is witnessed by Equiv.refl — the quotient graph and the coset graph with expanded connection set are the same graph up to the identity map on G ⧸ K. Together with #39530, #39548, and #39550, this gives a complete formalization of Chapters 1–2 of arXiv:1306.4798. Depends on #39550. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	755/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/QuotientGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean,Mathlib/Combinatorics/SimpleGraph/Symmetric.lean	6	5	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14050 10 days ago	10-14052 10 days ago	4-49821 4 days
39550	RaggedR author:RaggedR	feat(Combinatorics/SimpleGraph): Sabidussi representation theorem	This proves Sabidussi's representation theorem: if a group G acts transitively on the vertices of a graph Γ while preserving adjacency, then Γ is isomorphic to the coset graph `Sab(G, Gᵥ, D)` where `Gᵥ` is the stabilizer of a basepoint and `D = {g ∈ G : Γ.Adj v (g • v)}` is the connection set. For arc-transitive (symmetric) graphs, the connection set D is a single double coset HaH, giving the classical Sabidussi coset graph Sab(G, H, HaH). For merely vertex-transitive graphs, D may be a union of several double cosets. The connection set D is shown to satisfy the IsConnectionSet axioms for the stabilizer subgroup: it is stable under left and right multiplication by stabilizer elements (since the stabilizer fixes v and the action preserves adjacency), closed under inversion (since the graph is undirected), and disjoint from the stabilizer (since the graph has no loops). The orbit-stabilizer equivalence V ≃ G ⧸ Gᵥ is then shown to preserve adjacency in both directions, completing the isomorphism. The definitions and proofs are from my honours thesis (Symmetric Graphs and their Quotients, arXiv:1306.4798). Depends on #39548. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	423/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean,Mathlib/Combinatorics/SimpleGraph/Representation.lean	4	5	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14049 10 days ago	10-14051 10 days ago	4-50975 4 days
39548	RaggedR author:RaggedR	feat(Combinatorics/SimpleGraph): coset graphs (Sabidussi construction)	This adds coset graphs (Sabidussi's construction) to Mathlib, building on the graph action infrastructure from #39530. Given a group `G`, a subgroup `H`, and a connection set `D` (a union of `(H,H)`-double cosets, closed under inversion, disjoint from `H`), the coset graph `Sab(G, H, D)` is the simple graph on `G ⧸ H` where `xH` is adjacent to `yH` whenever `x⁻¹y ∈ D`. The well-definedness proof — that adjacency is independent of coset representatives — uses the double coset stability of `D`. This is the core algebraic content of the construction. The file then shows that left multiplication by `G` preserves adjacency (`graphAction` instance) and that coset graphs are vertex-transitive. When `H ≤ K`, the natural projection `G ⧸ H → G ⧸ K` is a graph homomorphism for coset graphs sharing the same connection set `D`. The proof of `proj_adj` is trivial — adjacency is `x⁻¹y ∈ D` in both graphs, independent of the subgroup. This is the Sabidussi analogue of quotient by a block system: the orbits of `K` on `G ⧸ H` form blocks of size `[K : H]`, and the quotient graph is `Sab(G, K, D)`. For example, the Zhou graph (F182A, Sab(PSL(2,13), S₃), 182 vertices, cubic) projects to the Zhou-6 graph (Sab(PSL(2,13), D₁₂), 91 vertices, 6-regular) via S₃ ≤ D₁₂, and the dodecahedron (Sab(A₅, C₃)) projects to the Petersen graph (Sab(A₅, D₆)) via C₃ ≤ D₆. Sabidussi's construction generalizes Cayley graphs (which are the special case `H = ⊥`). Together with the representation theorem (a future PR), it gives a complete classification: every vertex-transitive graph is isomorphic to a coset graph. The definitions and proofs are from my honours thesis (Symmetric Graphs and their Quotients, arXiv:1306.4798). Depends on #39530. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	304/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean,Mathlib/Combinatorics/SimpleGraph/CosetGraph.lean	3	5	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14048 10 days ago	10-14049 10 days ago	3-76269 3 days
39498	RaggedR author:RaggedR	feat(RingTheory/HopfAlgebra): umbral operators via generating functions	## Umbral operators via generating functions This PR completes the formalization of the finite operator calculus on `R[X]` over a ℚ-algebra. The entire umbral calculus — every theorem, every lemma, zero sorry's — is now machine-checked, from the coalgebra axioms (PR #39410) through Rota's classification (PR #39465) to the umbral operator and its duality theory. Given a delta operator `Q` on `R[X]`, the delta series `f(y) = Σ (Q(X^k)).eval 0 / k! · y^k` is a formal power series with zero constant term and unit linear coefficient. Its compositional inverse `g` (obtained via Mathlib's `substInvOfIsUnit`) encodes the basic sequence: the polynomial `p_n` has coefficients `(p_n).coeff k = descFact(n, n-k) · [y^n](g^k)`. The umbral operator `U_Q` is the linear extension of `X^n ↦ p_n`. The key result is the lowering property `Q(p_{n+1}) = (n+1) • p_n`. The proof uses the natural duality of the finite operator calculus — the derivative pairing `⟨h, p⟩ = Σ_k coeff_k(h) · k! · p.coeff k` between `R⟦X⟧` and `R[X]`. Under this pairing, Q's adjoint is multiplication by f (proved via the convolution formula for power series coefficients), orthogonality gives `⟨f^k, p_n⟩ = n! · δ_{kn}` (from the Jabotinsky matrix identity), and non-degeneracy closes it (upper-triangular with unit diagonal, by descending induction). Three lines of mathematics, backed by a clean chain of lemmas. Once lowering is established, `umbralPoly_isBasicSequence` follows immediately, and `IsBasicSequence.isBinomialType` (from #39465) gives the coalgebra endomorphism property — completing the circle back to the Hopf algebra structure. References: Langer, Macdonald Polynomials and Symmetric Functions (arXiv:0907.3950), §1.2.2; Roman, The Umbral Calculus, Academic Press 1984, Ch. 2. Depends on #39410, #39465. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-ring-theory new-contributor LLM-generated	2141/0	Mathlib.lean,Mathlib/RingTheory/HopfAlgebra/BinomialType.lean,Mathlib/RingTheory/HopfAlgebra/DeltaOperator.lean,Mathlib/RingTheory/HopfAlgebra/Polynomial.lean,Mathlib/RingTheory/HopfAlgebra/UmbralOperator.lean	5	6	['RaggedR', 'github-actions', 'mathlib-bors']	nobody	10-14045 10 days ago	10-14047 10 days ago	1-2385 1 day
39465	RaggedR author:RaggedR	feat(RingTheory/HopfAlgebra): delta operators and Rota's classification	This formalizes the fundamental theorem of the umbral calculus: that the basic sequence of any delta operator is a sequence of binomial type. A delta operator on R[X] is a shift-equivariant linear operator which is essentially a formal power series in the variable d/dx. Rota's classification theorem states that the images of monomials x^n under delta operators are sequences of binomial type. This PR defines `IsBinomialType`, `IsShiftEquivariant`, `IsDeltaOperator`, `forwardDiff`, and `IsBasicSequence`. It proves that monomials and falling factorials are of binomial type, that the derivative and forward difference are delta operators, and that basic sequences are of binomial type (Rota's classification). The mathematical content is from the first half of my masters thesis (arXiv:0907.3950). See also Rota, Kahaner, and Odlyzko, Finite Operator Calculus (JMAA 42, 1973) and Roman, The Umbral Calculus (Academic Press, 1984). Depends on #39410. --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-ring-theory new-contributor LLM-generated	1386/0	Mathlib.lean,Mathlib/RingTheory/HopfAlgebra/BinomialType.lean,Mathlib/RingTheory/HopfAlgebra/DeltaOperator.lean,Mathlib/RingTheory/HopfAlgebra/Polynomial.lean	4	8	['RaggedR', 'github-actions', 'mathlib-bors', 'wwylele']	nobody	10-14044 10 days ago	10-14046 10 days ago	0-78204 21 hours
39530	RaggedR author:RaggedR	feat(Combinatorics/SimpleGraph): group actions on simple graphs	This adds the first connection between Mathlib's MulAction and SimpleGraph libraries. The GraphAction class asserts that a group action on the vertex type preserves the adjacency relation, and builds on it to define vertex-transitivity and arc-transitivity for graphs. The GraphAction typeclass gives adj_smul_iff (the biconditional for group actions) and toIso (each group element induces a graph automorphism). The IsVertexTransitive class combines GraphAction with IsPretransitive, and IsArcTransitive requires transitivity on ordered adjacent pairs (arcs). The main theorem is the standard characterization: a graph is arc-transitive if and only if it is vertex-transitive and locally transitive (the stabilizer of each vertex acts transitively on its neighbors). The forward direction is proved directly by composing a vertex-transporting element with a neighbor-transporting stabilizer element. The reverse direction shows that an arc-transitive graph with no isolated vertices is vertex-transitive. These definitions are the algebraic graph theory prerequisites for formalizing coset graphs (Sabidussi's construction) and the characterization of symmetric graphs via double cosets and involutions (Lorimer's theorem). --- LLM tools were used to assist with Lean formalization. The mathematical content is the author's own work.	t-combinatorics new-contributor LLM-generated	130/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Action.lean	2	7	['RaggedR', 'b-mehta', 'github-actions', 'mathlib-bors']	nobody	10-14032 10 days ago	10-14032 10 days ago	14-67671 14 days
31796	dobronx1325 author:dobronx1325	feat(Data/Real/EReal): add mul_lt_mul_of_pos_left theorem	This PR adds the theorem `EReal.mul_lt_mul_of_pos_left`, which states that for a positive real number `a` and extended reals `b < c`, left multiplication by `a` preserves the strict order: `(a : EReal) * b < (a : EReal) * c`. The theorem complements existing order-preserving properties for addition in `EReal` and extends the algebraic structure for multiplication. The proof uses basic properties of extended reals and order relations. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor merge-conflict	23/0	Mathlib/Data/EReal/Operations.lean	1	5	['JovanGerb', 'LLaurance', 'dobronx1325', 'github-actions', 'mathlib-merge-conflicts']	nobody	10-11641 10 days ago	189-9769 189 days ago	6-21252 6 days
38194	ryanncode author:ryanncode	feat(LinearAlgebra/BilinearForm): add indefinite metrics	Add the `IndefiniteMetric` structure to support vector spaces equipped with a non-degenerate, symmetric, indefinite bilinear form. Provide the algebraic foundation for indefinite inner product spaces by formalizing the metric via `LinearMap.BilinForm` and extracting its associated quadratic form without enforcing the `IsPosSemidef` typeclass. Previously, mathlib required strictly positive-definite metrics to instantiate inner product spaces (`InnerProductSpace`), which prevented the formalization of indefinite geometries without causing typeclass inference failures. Bridge this gap by isolating the symmetric bilinear form from topological and positivity constraints, allowing the library to handle generalized indefinite metric spaces safely. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor label:t-algebra$	47/0	Mathlib.lean,Mathlib/LinearAlgebra/BilinearForm/IndefiniteMetric.lean	2	5	['dagurtomas', 'github-actions', 'mathlib-merge-conflicts', 'ryanncode']	nobody	10-6232 10 days ago	10-5650 10 days ago	13-80182 13 days
35834	homeowmorphism author:homeowmorphism	feat(Mathlib/GroupTheory/PresentedGroup): every group has a presentation	We show that every group has a presentation defined by taking the free group with all of the group elements as the generators, and defining the relations as the kernel of the induced subjective homomorphism from that free group to the group itself. Use of AI: This has been vibe-coded with GPT-Codex-5.3, was updated through review, and was double-checked by the author. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor t-group-theory large-import awaiting-author LLM-generated merge-conflict	29/1	Mathlib/GroupTheory/PresentedGroup.lean	1	16	['copilot-pull-request-reviewer', 'euprunin', 'github-actions', 'homeowmorphism', 'mathlib-bors', 'mathlib-merge-conflicts', 'plp127', 'tb65536']	tb65536 assignee:tb65536	9-78124 9 days ago	88-62657 88 days ago	4-29717 4 days
39212	emlis42 author:emlis42	feat(Algebra/ContinuedFractions): add `partNums!` and `partDens!`	This PR adds `partNums!` and `partDens!`, which provide infinite stream representations for the sequences of partial numerators and denominators of a generalized continued fraction.	t-algebra new-contributor label:t-algebra$	8/0	Mathlib/Algebra/ContinuedFractions/Basic.lean	1	4	['emlis42', 'github-actions', 'grunweg']	nobody	9-77172 9 days ago	9-76518 9 days ago	21-77317 21 days
37964	mortarsanjaya author:mortarsanjaya	feat(Algebra/Order/Floor): weaken assumptions on theorems about `FloorRing`	This PR weakens as much assumptions as possible on theorems about `FloorSemiring` and `FloorRing`. Mainly, `IsOrderedRing` and `IsStrictOrderedRing` are weakened to just `IsOrderedAddMonoid` or removed completely from the assumptions on the theorems. Most theorems can be generalized as is or only requires a minor modification of replacing lemmas about casting naturals/integers preserving order (the likes of `Nat.cast_le`, `Int.cast_lt`, etc.) with the corresponding version for `FloorRing`. Some other lemmas require modification in the proofs, but these changes shorten the proofs. The new proof of the theorem `Int.mul_cast_floor_div_cancel_of_pos` requires an extra import. The assumption `IsOrderedAddMonoid` is required on lemmas that involve comparison + addition, and `IsOrderedRing` is required only on lemmas that involve comparison + multiplication of two non-integer elements. --- - [ ] depends on: #37714 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-algebra new-contributor blocked-by-other-PR merge-conflict label:t-algebra$	349/266	Mathlib/Algebra/ContinuedFractions/Computation/Approximations.lean,Mathlib/Algebra/ContinuedFractions/Computation/TerminatesIffRat.lean,Mathlib/Algebra/Order/Floor/Defs.lean,Mathlib/Algebra/Order/Floor/Ring.lean,Mathlib/Algebra/Order/Floor/Semiring.lean,Mathlib/Algebra/Order/Round.lean,Mathlib/Data/Int/Log.lean,Mathlib/Data/Rat/Floor.lean,Mathlib/Topology/Algebra/Order/Floor.lean	9	5	['github-actions', 'mathlib-dependent-issues', 'mathlib-merge-conflicts']	nobody	9-76672 9 days ago	50-53839 50 days ago	0-363 6 minutes
38390	mortarsanjaya author:mortarsanjaya	feat(Data/Nat/Cast/Order/Basic): introduce new class `IsMonotoneNatCast`	The class says that `Nat.cast` is monotone in an `AddMonoidWithOne`. Basically, we use this class when we only care about comparing the elements of a monoid that comes from the `Nat`s (so we do not have to care about the compatibility between the additive structure of the monoid and its order structure). --- Other than that, I'm also reorganizing some section naming, and I change the proof of the `Nontrivial` instance at the bottom to using `NeZero.nontrivial`. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-data new-contributor merge-conflict	28/18	Mathlib/Data/Nat/Cast/Order/Basic.lean	1	8	['github-actions', 'leanprover-radar', 'mathlib-bors', 'mathlib-merge-conflicts', 'mortarsanjaya', 'vihdzp']	nobody	9-76534 9 days ago	32-59210 32 days ago	7-82717 7 days
37716	slavanaprienko author:slavanaprienko	feat(LinearAlgebra/Matrix/Determinant): Desnanot-Jacobi identity	This PR adds the Desnanot-Jacobi identity (also known as the Lewis Carroll identity or Dodgson condensation): for any (n+2)×(n+2) matrix M over a commutative ring, $$\det(M) \cdot \det(M_{1,n}^{1,n}) = \det(M_1^1) \cdot \det(M_n^n) - \det(M_1^n) \cdot \det(M_n^1)$$ The proof follows Bressoud's Proofs and Confirmations (Cambridge University Press, 1999): multiply M by an auxiliary matrix built from columns of the adjugate, then compare determinants. This yields the identity premultiplied by det(M). To cancel, we pass to a universal polynomial ring (an integral domain with nonzero determinant), then specialize back to arbitrary commutative rings. It seems there's some interest in adding this: https://leanprover.zulipchat.com/#narrow/channel/217875-Is-there-code-for-X.3F/topic/Determinantal.20identity.20and.20the.20Cauchy.20matrix.20determinant/with/582946873 ---	t-algebra new-contributor label:t-algebra$	217/0	Mathlib.lean,Mathlib/LinearAlgebra/Matrix/Determinant/DesnanotJacobi.lean	2	13	['SnirBroshi', 'github-actions', 'grunweg', 'kim-em', 'slavanaprienko']	nobody	9-57681 9 days ago	9-57105 9 days ago	23-15493 23 days
35753	Vilin97 author:Vilin97	feat(Topology/Algebra/Order): regular grid helpers and piecewise linear interpolation	Make API for piecewise linear interpolation on regular grids. I need these to for ODE time-stepping methods, like forward Euler, and later Runge–Kutta methods. Follow-up PR: #35755 (forward Euler method convergence). I don't know if these numerical analysis ODE-solving methods even belong in mathlib. If someone could advise me on it, I would appreciate it. --- The initial proof was produced by [Aristotle](https://aristotle.harmonic.fun). The code was iteratively refined (factoring out lemmas, golfing, simplifying proofs) using Claude Code. - [ ] depends on: #38091	t-topology new-contributor LLM-generated maintainer-merge	201/0	Mathlib.lean,Mathlib/Topology/Algebra/Order/PiecewiseLinear.lean	2	59	['Vilin97', 'YanYablonovskiy', 'adomani', 'botbaki-review', 'copilot-pull-request-reviewer', 'dagurtomas', 'eric-wieser', 'github-actions', 'grunweg', 'j-loreaux', 'mathlib-dependent-issues', 'wwylele']	ADedecker assignee:ADedecker	9-48642 9 days ago	31-60225 31 days ago	64-13935 64 days
29151	yuanyi-350 author:yuanyi-350	feat: Corollary of Hahn–Banach theorem	In this PR, I have proved [Rudin, Functional Analysis (Theorem 3.7)][rudin1991] which is a step in proving the Closed Range Theorem. Also, I have added tags for the corresponding theorems in Rudin to mathlib. 3.7 Theorem. Suppose B is a convex, balanced, closed set in a locally convex space $X, x_0 \in X$, but $x_0 \notin B$. Then there exists $\Lambda \in X^$ such that $\|\Lambda x\| \leq 1$ for all $x \in B$, but $\Lambda x_0>1$ proof. Since $B$ is closed and convex, we can apply (b) of Theorem 3.4, with $A=\{ x_0 \}$ , to obtain $\Lambda_1 \in X^$ such that $\Lambda_1 x_0=r e^{i \theta}$ lies outside the closure $K$ of $\Lambda_1(B)$. Since $B$ is balanced, so is $K$. Hence there exists $s, 0 List.Vector.* - ... Deletions: - Nat.bit1_add_bit1 - ... Any other comments you want to keep out of the PR commit should go below the `---`, and placed outside this HTML comment, or else they will be invisible to reviewers. If this PR depends on other PRs, please list them below this comment, using the following format: - [ ] depends on: #xyz [optional extra text] --> [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	awaiting-author new-contributor t-analysis	69/2	Mathlib/Analysis/LocallyConvex/Separation.lean,Mathlib/Analysis/RCLike/Lemmas.lean,Mathlib/Topology/Order/OrderClosed.lean	3	17	['faenuccio', 'fpvandoorn', 'github-actions', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot', 'mcdoll', 'themathqueen', 'yuanyi-350']	faenuccio assignee:faenuccio	9-8868 9 days ago	254-17253 254 days ago	2-2914 2 days
29777	yuanyi-350 author:yuanyi-350	feat(Functional Analysis): closed Range Theorem	- [ ] depends on: #29151 [Corollary of Hahn-Banach theorem] - [ ] depends on: #29776 [refactor ContinuousLinearMap.isOpenMap by separating it into sublemmas] --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	WIP blocked-by-other-PR new-contributor awaiting-author t-analysis	236/25	Mathlib/Analysis/LocallyConvex/Separation.lean,Mathlib/Analysis/Normed/Operator/Banach.lean,Mathlib/Analysis/Normed/Operator/ClosedRange.lean,Mathlib/Analysis/RCLike/Lemmas.lean,Mathlib/Topology/Order/OrderClosed.lean	5	5	['github-actions', 'mathlib-merge-conflicts', 'mathlib4-dependent-issues-bot', 'mathlib4-merge-conflict-bot']	faenuccio assignee:faenuccio	9-8794 9 days ago	256-85978 256 days ago	0-590 9 minutes
39146	anovickis author:anovickis	feat(Analysis/CStarAlgebra/Matrix): CompactSpace instances for unitaryGroup and specialUnitaryGroup	Adds `CompactSpace` instances (and supporting `IsClosed` / `IsCompact` lemmas) for the matrix unitary and special unitary groups. The compactness follows from Heine-Borel applied to the entrywise sup norm: every unitary matrix has all entries bounded by `1` (via the existing `entry_norm_bound_of_unitary` lemma), and `Matrix n n 𝕜` is finite-dimensional, so `closed + bounded ⇒ compact`. ### New declarations - `isClosed_unitaryGroup`, `isCompact_unitaryGroup` - `instance Matrix.unitaryGroup.instCompactSpace` - `isClosed_specialUnitaryGroup`, `isCompact_specialUnitaryGroup` - `instance Matrix.specialUnitaryGroup.instCompactSpace` All placed inside the existing `EntrywiseSupNorm` section in `Mathlib/Analysis/CStarAlgebra/Matrix.lean`, so the `Matrix.Norms.Elementwise` scope used for the bound is already in scope. ### Motivation These instances enable downstream constructions of compact matrix Lie groups such as flag manifolds (e.g. SU(3)/T = F₂), where the quotient inherits compactness for free via `Quotient.compactSpace`. They also fill an obvious gap in the matrix-group API: `unitary R` is known to be closed, but compactness for `Matrix.unitaryGroup` was not previously available as an instance. Claude Code / Anthropic was used for generating the code, Verification was done with lake build, each lemma reviewed. Proofs came out of F2 mass gap lean library - so compile verified	t-analysis new-contributor awaiting-author	52/0	Mathlib/Analysis/CStarAlgebra/Matrix.lean	1	12	['anovickis', 'github-actions', 'j-loreaux', 'wwylele']	nobody	8-73209 8 days ago	22-65217 22 days ago	0-6851 1 hour
39791	zixiaowang17 author:zixiaowang17	feat(Probability/HypothesisTesting): add Neyman-Pearson lemma	This PR adds `Probability/HypothesisTesting/NeymanPearson.lean`, formalizing the classical Neyman-Pearson lemma with reference Ingster, Y. and Suslina, I.A., 2012. Nonparametric goodness-of-fit testing under Gaussian models (Vol. 169). Springer Science & Business Media. -/ The main definitions are: * `ProbabilityTheory.NeymanPearson.npLikelihoodRatio` * `ProbabilityTheory.NeymanPearson.npTest` * `ProbabilityTheory.NeymanPearson.npSumError` The main theorem is: * `ProbabilityTheory.NeymanPearson.neyman_pearson` We state the theorem in the weighted form `∫ T dP + t * ∫ (1 - T) dQ`, over measurable tests T : Ω → ℝ with values in [0, 1], using P + Q as the canonical dominating measure; rather than starting with the constrained formulation that fixes the Type I error and minimizes the Type II error. The reasons are two fold. First, it can be thought as the Lagrangian form of the classical constrained Neyman-Pearson problem. Second, this weighted form is often arises in applications, such as, in minimax lower-bound arguments for functional estimation, where one typically reduces estimation lower bounds to testing inequalities involving weighted sums of error probabilities. Worflow with AI: we first manually wrote a blueprint in latex with every definition and lemma we need [NL_Blueprint_NP_Lemma.pdf](https://github.com/user-attachments/files/28199645/NL_Blueprint_NP_Lemma.pdf). then we checked the Mathlib API with claude code, chatgpt and LeanSearch, We manually wrote the outline, in the outline version we deleted the discussion on gamma in the blueprint - since we have used the version of the NP lemma that uses the likelihood ratio to construct the test, rather than writing in terms of comparisons of Radon-Nikodym derivatives with a common dominating measure, and hence have used gamma to arbitrarily define likelihood-ratio sets of measure zero under the null hypothesis. This choice is motivated by the downstream derivation of errors of NP tests. since we are unfamiliar with mathlib naming style, we used claude code skill for proof golfing and some syntax correction, eg whether should use unfold or simp only []; Co-authored-by: Rajarshi Mukherjee ---	t-measure-probability new-contributor LLM-generated	179/0	Mathlib.lean,Mathlib/Probability/Decision/HypothesisTesting/NeymanPearson.lean	2	3	['github-actions', 'grunweg']	nobody	8-61889 8 days ago	unknown	unknown
39436	dtumad author:dtumad	chore: Add `seqLeft` and `seqRight` unfolding to monad_norm simp set	This PR adds `seqLeft_eq_bind` and `seqRight_eq_bind` to `monad_norm`, so that `<` and `>` get unfolded in the same way as `<*>` already does when using the `simp` set. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta new-contributor	1/1	Mathlib/Tactic/Attr/Core.lean	1	2	['github-actions']	dwrensha assignee:dwrensha	8-49691 8 days ago	8-46188 8 days ago	17-55888 17 days
38214	emlis42 author:emlis42	feat(Algebra/ContinuedFractions): add Euler's continued fraction	This PR formalizes Euler’s continued fractions by providing `Euler` which construct one by giving head term and coefficients with some basic property. We also introduce a transformation `GenContFract.toEuler` that maps a generalized continued fraction `g : GenContFract K` to an equivalent Euler-form continued fraction.	new-contributor t-algebra label:t-algebra$	262/0	Mathlib.lean,Mathlib/Algebra/ContinuedFractions/Euler.lean	2	15	['github-actions', 'mathlib-bors', 'wwylele']	alreadydone assignee:alreadydone	8-48530 8 days ago	39-76665 39 days ago	39-78759 39 days
39256	Sfgangloff author:Sfgangloff	feat(SymbolicDynamics): add monotonicity lemma for LanguageOn	In Symbolic dynamics. Proof that the language of a set of configurations is monotone with respect to inclusion of configuration sets: X ⊆ Y → LanguageOn X U ⊆ LanguageOn Y U The proof is a direct unfolding of definitions: a pattern in the language of X comes from restricting some configuration x ∈ X, and inclusion X ⊆ Y allows the same witness to be used for Y. Related to issue #39252	t-dynamics new-contributor	9/1	Mathlib/Dynamics/SymbolicDynamics/Basic.lean	1	3	['github-actions']	ADedecker assignee:ADedecker	8-48529 8 days ago	20-85922 20 days ago	20-85697 20 days
38334	8e7 author:8e7	feat(Combinatorics/SimpleGraph/TreeDecomp): define tree decompositions	Add definition for tree decompositions on simple graphs. Define the tree width of a simple graph and prove basic statements and conversions. ```lean structure TreeDecomp (G : SimpleGraph V) where /-- The type of bags in the tree. -/ W : Type /-- The set of vertices in each bag. -/ 𝓧 : W → Finset V /-- The graph adjacency relation of bags. -/ T : SimpleGraph W /-- T must be a tree. -/ isTree : IsTree T /-- All vertices in G must appear in some bag. -/ vertexCover : ∀ v : V, ∃ w : W, v ∈ 𝓧 w /-- For any edge (u, v) in G, there is a bag containing both u and v. -/ edgeCover ⦃u v : V⦄ : G.Adj u v → ∃ w : W, u ∈ 𝓧 w ∧ v ∈ 𝓧 w /-- For any vertex v in G, the set of bags that contain v is preconnected. -/ connectedBags : ∀ v : V, (T.induce ({w \| v ∈ 𝓧 w})).Preconnected ``` AI Usage: Some proofs are written with the help of Claude Code, and everything has been manually reviewed. --- - [ ] depends on: #38027 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	new-contributor blocked-by-other-PR t-combinatorics LLM-generated	467/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Star.lean,Mathlib/Combinatorics/SimpleGraph/TreeDecomp.lean	3	6	['8e7', 'github-actions', 'mathlib-dependent-issues']	nobody	8-24282 8 days ago	unknown	unknown
39701	thothrde author:thothrde	feat(Condensed/Solid): prove profiniteSolidification is iso at finite types (partial)	Proves partial results toward the open TODO in `Mathlib/Condensed/Solid.lean`: > TODO (hard): prove that `((profiniteSolid ℤ).obj S).IsSolid` for `S : Profinite`. ## New lemmas ### `CondensedMod.profiniteSolidCounit_isIso` The counit `(profiniteSolidCounit R).app T` is an isomorphism for every `T : FintypeCat`. Proof: `IsPointwiseRightKanExtension.isIso_hom` (using that `FintypeCat.toProfinite` is fully faithful) gives `IsIso (profiniteSolidCounit R)` as a natural transformation, and then `inferInstance` extracts the component-wise isomorphism. ### `CondensedMod.profiniteSolidification_comp_counit` The solidification composed with the counit equals the identity at `FintypeCat` objects: ``` (profiniteSolidification R).app (FintypeCat.toProfinite.obj T) ≫ (profiniteSolidCounit R).app T = 𝟙 _ ``` Proof: Direct from `liftOfIsRightKanExtension_fac_app`, since `profiniteSolidification` is defined as a `liftOfIsRightKanExtension`. ### `CondensedMod.profiniteSolidification_isIso_at_fintype` The solidification map is an isomorphism at every `FintypeCat.toProfinite.obj T`. Proof: Since solidification ≫ counit = id and counit is an isomorphism, `isIso_of_comp_hom_eq_id` gives that solidification = inv(counit), hence is also an isomorphism. ### `CondensedMod.profiniteSolid_isSolid_at_fintype` Partial result: `((profiniteSolid R).obj S).IsSolid` holds when the test object is `FintypeCat.toProfinite.obj T`. Proof: `profiniteSolidification_isIso_at_fintype` makes the solidification map an isomorphism in `CondensedMod R`; functoriality of `yoneda` then gives the isomorphism on hom-sets. ### `CondensedMod.profiniteSolid_obj_isSolid` (with `sorry`) States the full result. The remaining step requires showing that: 1. Every `X : Profinite` is a cofiltered limit of finite discrete quotients (`X.asLimit` from `Mathlib.Topology.Category.Profinite.AsLimit`, now imported). 2. The solid module condition is preserved under such limits. Point (2) follows from the adjunction `solidification ⊣ inclusionOfSolidModules`, which implies the inclusion preserves limits (being a right adjoint). This adjunction has not yet been formalized in Mathlib, and constitutes the remaining hard step. ## Open question The `sorry` in `profiniteSolid_obj_isSolid` can be removed once the following is formalized: ```lean lemma isSolid_of_isLimit {J : Type*} [SmallCategory J] {F : J ⥤ CondensedMod R} (c : Cone F) (hc : IsLimit c) (h : ∀ j, (F.obj j).IsSolid) : c.pt.IsSolid ``` This requires the adjunction between the solidification functor and the inclusion of solid modules into condensed modules. ## Changes - Added `import Mathlib.Topology.Category.Profinite.AsLimit` (needed for `X.asLimit`) - Added 4 new lemmas + 1 theorem (with sorry) to `Mathlib/Condensed/Solid.lean` - Replaced the old TODO comments with structured documentation ## Notes This PR is a work in progress. The four new lemmas are fully proved (no sorry). The main theorem `profiniteSolid_obj_isSolid` contains one sorry with a detailed proof sketch in its docstring. The leanprover-community CI will show one sorry warning, which is intentional and documented.	t-condensed new-contributor	652/8	MathProject/P0_SolLeftCancel_Axiom.lean,MathProject/P1_Solid.lean,MathProject/P2_finFree_Solid.lean,MathProject/P4_Solid_Progress.lean,MathProject/PR_README.md,Mathlib/Algebra/Category/ModuleCat/Adjunctions.lean,Mathlib/Condensed/Solid.lean	7	2	['github-actions']	nobody	8-18964 8 days ago	unknown	unknown
38669	dannyply author:dannyply	feat(Topology/Algebra/PontryaginDual): prove compact monoids have discrete duals	Proves that the Pontryagin dual of a compact monoid is discrete. As a consequence, it also adds the corresponding finite-type instances for compact discrete monoids. This upstreams a result first added downstream in [`YaelDillies/APAP`](https://github.com/YaelDillies/APAP), where this fact was needed to close a `sorry`. The proof separates the trivial character from all the others using the right half of the circle and adds a few reusable `Circle` helper lemmas near the existing related API. The original APAP proof was AI-assisted and then reviewed/rewritten during downstream review. For this PR, I used Codex to help adapt the APAP proof to mathlib and to refactor the supporting lemmas. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-topology new-contributor	130/16	Mathlib/Analysis/SpecialFunctions/Complex/Circle.lean,Mathlib/Topology/Algebra/PontryaginDual.lean,Mathlib/Topology/MetricSpace/Pseudo/Defs.lean	3	30	['dannyply', 'github-actions', 'j-loreaux', 'tb65536']	j-loreaux assignee:j-loreaux	8-8263 8 days ago	8-8263 8 days ago	8-81558 8 days
39820	samuelchassot author:samuelchassot	Add proof of the existence of an Eulerian walk if all vertices have even degree or if exactly vertices have odd degree	As per the TODO open in `Trails.lean`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor	671/3	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Eulerian.lean,Mathlib/Combinatorics/SimpleGraph/Trails.lean	3	8	['SnirBroshi', 'copilot-pull-request-reviewer', 'github-actions']	nobody	8-7105 8 days ago	8-7498 8 days ago	8-7248 8 days
31898	ntapiam author:ntapiam	feat(LinearAlgebra/TensorAlgebra): implement HopfAlgebra for TensorAlgebra	implementation of the natural Hopf algebra structure on the TensorAlgebra	new-contributor t-ring-theory awaiting-author merge-conflict	253/0	Mathlib.lean,Mathlib/Algebra/FreeAlgebra.lean,Mathlib/LinearAlgebra/TensorAlgebra/Basic.lean,Mathlib/RingTheory/Bialgebra/FreeAlgebra.lean,Mathlib/RingTheory/Bialgebra/TensorAlgebra.lean,Mathlib/RingTheory/HopfAlgebra/TensorAlgebra.lean	6	66	['YaelDillies', 'github-actions', 'hawkrobe', 'kckennylau', 'mathlib-merge-conflicts', 'ntapiam']	nobody	7-65667 7 days ago	191-51427 191 days ago	0-30128 8 hours
39849	hawkrobe author:hawkrobe	feat(RingTheory): Every connected graded bialgebra is a Hopf algebra	--- see [#PR reviews > #31898 implement HopfAlgebra for TensorAlgebra @ 💬](https://leanprover.zulipchat.com/#narrow/channel/144837-PR-reviews/topic/.2331898.20implement.20HopfAlgebra.20for.20TensorAlgebra/near/597455260). - [ ] depends on: #39785 - [ ] depends on: #39841 I used Claude Code to plan and audit.	t-ring-theory new-contributor blocked-by-other-PR	732/23	Mathlib.lean,Mathlib/RingTheory/Bialgebra/Graded.lean,Mathlib/RingTheory/Bialgebra/Primitive.lean,Mathlib/RingTheory/Coalgebra/Graded.lean,Mathlib/RingTheory/HopfAlgebra/Basic.lean,Mathlib/RingTheory/HopfAlgebra/Graded.lean,Mathlib/RingTheory/HopfAlgebra/Primitive.lean,Mathlib/RingTheory/HopfAlgebra/TensorProduct.lean	8	3	['github-actions', 'mathlib-dependent-issues']	nobody	7-58046 7 days ago	unknown	unknown
39505	dannyhe652 author:dannyhe652	feat(SimpleGraph): add Vizing's theorem for edge coloring	Hi! I'm a high school student interested in formulization of mathematics in Lean. Recently, I have worked on a project to formulize Vizing Theorem with Daniel Raggi from Cambridge University with AI assistance. In particular, we first drafted an outline for the proof, and built the proof using Claude Opus 4.5 and 4.6. The proof is optimized using Aristotle and finally reviewed by ourselves. We rewrote some parts of the code and some comments. The code now builds cleanly and we wish this code to be reviewed by Lean Community. I am aware that there are previous attempts, some being successful, on formulizing Vizing Theorem, including this one by Arohee https://github.com/aroheebhoja/vizing. However, I believe that no PR have been made. Our proof is not based on his proof, but it could be helpful for the community to review that project as well. I sincerely thank everyone who has time to verify and review our code. A summary of the project is as follows. Please contact me if there are any questions or problems. ## Summary This PR completes the proof of Vizing's theorem for edge coloring in simple graphs, proving that the chromatic index of any graph is either Δ (the maximum degree) or Δ + 1. ## Changes ### New files - `Mathlib/Combinatorics/SimpleGraph/Coloring/EdgeColoring.lean` — Core definitions - `edgeColoring`: Type for line graph colorings - `edgeColorable`: Graph is edge-colorable with n colors - `chromaticIndex`: Chromatic index as ℕ - `Mathlib/Combinatorics/SimpleGraph/Coloring/KempeChain.lean` — Kempe Chain - Coloring observables: `incidentEdges`, `incidentColors`, `missingColors` - Kempe subgraph structure with bounded degree - `swapKempe`: Recolor edges in a connected component via color-swapping - `Mathlib/Combinatorics/SimpleGraph/Coloring/VizingFan.lean` — Vizing Fan Rotation - `IsFan`: Vizing fan structure with special color properties - Fan maximality and dichotomy on terminal vertices - `rotate_termA`: Extend coloring when a free color exists at both endpoints - `vizingAdjacencyLemma`: Main adjacency lemma for both cases - `Mathlib/Combinatorics/SimpleGraph/Coloring/VizingTheorem.lean` — Main theorems - `edge_eq_of_color_eq`: Proper edge colorings assign different colors to distinct edges sharing a vertex - `maxDegree_le_chromaticIndex`: χ'(G) ≥ Δ(G) - `chromaticIndex_bot`: Empty graph has chromatic index 0 - `vizingUpperBound_aux`: Inductive proof of upper bound on number of edge - `vizingTheorem`: χ'(G) ∈ {Δ(G), Δ(G) + 1} ### Modified files - `Mathlib.lean` — Added imports for the four new coloring modules ## Technical Approach Lower bound (χ'(G) ≥ Δ): - Edges incident to a max-degree vertex form a clique in the line graph - Clique number lower-bounds chromatic number Upper bound (χ'(G) ≤ Δ + 1): - Induction on the number of edges - Base case: empty graph colored with 0 colors - Inductive step: - If a free color exists at both endpoints of an edge, then extend directly - Otherwise: - Build a maximal fan from one endpoint - Apply dichotomy: either extend via Term-A (free color at both endpoints) or Term-B (Kempe swap) - Term-B uses a three-vertex connectivity argument to derive a contradiction, forcing the fan to extend ## Key Lemmas - `incidentEdges`, `incidentColors`, `missingColors`: Coloring observables at vertices - `kempeSubgraph`: Restricted subgraph of edges with two specific colors - `swapKempe`: Recolor via Kempe chain swapping - `IsFan.singleton`: Trivial fan always valid - `IsFan.length_le_card`: Fan length is bounded by vertex count - `IsFan.dichotomy`: Maximal fan satisfies Term-A or Term-B - `IsFan.rotate_termA`: Term-A case extends the coloring inductively - `vizingAdjacencyLemma`: Handles both cases for extending one edge - `vizingUpperBound_aux`: Framework for full inductive proof - `edge_eq_of_color_eq`: Distinctness of edges with same color ## Testing All four modules compile with no `sorry` nor errors or warnings. ## References * V. G. Vizing, On an estimate of the chromatic class of a p-graph, Diskret. Analiz. 3 (1964), 25–30. ## Co-authors Co-authored-by: Daniel Raggi Co-authored-by: Aristotle (Harmonic) Co-authored-by: Claude Opus 4.5 & 4.6 --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor LLM-generated	1915/0	Mathlib.lean,Mathlib/Combinatorics/SimpleGraph/Coloring/EdgeColoring.lean,Mathlib/Combinatorics/SimpleGraph/Coloring/KempeChain.lean,Mathlib/Combinatorics/SimpleGraph/Coloring/VizingFan.lean,Mathlib/Combinatorics/SimpleGraph/Coloring/VizingTheorem.lean	5	3	['github-actions']	nobody	7-52650 7 days ago	7-52082 7 days ago	15-52781 15 days
39722	kg583 author:kg583	feat(Combinatorics): Link `Nat.Partition` to `YoungDiagram`	--- AI disclosure: Claude was used to source some proof sketches. [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics new-contributor large-import	120/4	Mathlib.lean,Mathlib/Combinatorics/Enumerative/Partition/Basic.lean,Mathlib/Combinatorics/Enumerative/Partition/Conjugate.lean,Mathlib/Combinatorics/Young/YoungDiagram.lean	4	36	['NoahW314', 'github-actions', 'kg583', 'wwylele']	nobody	7-42131 7 days ago	8-67394 8 days ago	10-57258 10 days
38275	TTony2019 author:TTony2019	feat: Add `AffineEquiv.image_intrinsicInterior`	## Summary This PR generalizes the existing lemma `AffineIsometry.image_intrinsicInterior` to the setting of affine equivalences, yielding the corresponding result `AffineEquiv.image_intrinsicInterior`. Since affine equivalences are more general than affine isometries, the proof requires an additional finite-dimensionality assumption. The key extra input is that in finite-dimensional spaces, an affine equivalence induces a homeomorphism via `AffineEquiv.toHomeomorphOfFiniteDimensional`, so the assumptions are adjusted accordingly. Apart from these extra assumptions, the argument is essentially the same as for `AffineIsometry.image_intrinsicInterior`. ## Collaboration This PR was developed together with @imathwy.	t-analysis new-contributor	283/41	Mathlib/Analysis/Convex/Intrinsic.lean,Mathlib/Analysis/Normed/Module/FiniteDimension.lean,Mathlib/LinearAlgebra/AffineSpace/Restrict.lean,Mathlib/Topology/Algebra/AffineSubspace.lean,Mathlib/Topology/Homeomorph/Defs.lean	5	29	['TTony2019', 'github-actions', 'imathwy', 'j-loreaux', 'themathqueen']	j-loreaux assignee:j-loreaux	7-23557 7 days ago	7-23557 7 days ago	24-11084 24 days
35733	mkaratarakis author:mkaratarakis	feat: Algebraic setup and matrix coefficients for Gelfond-Schneider theorem	This PR introduces the foundational algebraic setup and coefficient bounds required for the proof of the Gelfond-Schneider Theorem (Hilbert's Seventh Problem), which establishes that for algebraic numbers $\alpha \neq 0, 1$ and irrational algebraic $\beta$, the number $\alpha^\beta$ is transcendental. Following the contradiction argument presented in Loo-Keng Hua's "Introduction to Number Theory" (Chapter 17.9, 490 -493) Gelfond's Proof), this file constructs the common number field $K$ and sets up the scaled algebraic integers for the auxiliary linear system. This system will later be solved via Siegel's lemma (Lemma 8.2, 490, Hua). This PR is essentially the first half of page 490 in the book. The proof proceeds by assuming $\gamma = \alpha^\beta$ is algebraic, meaning $\alpha$, $\beta$, and $\gamma$ all lie in an algebraic field $K$ of degree $h$. 1. Bundles the common number field $K$, the complex embeddings, and the algebraic preimages $\alpha', \beta', \gamma'$, alongside the core hypotheses of the theorem. 2. Defines the field degree $h = [K : \mathbb{Q}]$, and bounds $m = 2h + 2$ and $n = q^2 / (2m)$ to control the dimensions of the linear system. 3. Defines $c_1$, a natural number chosen so that $c_1 \alpha$, $c_1 \beta$, and $c_1 \gamma$ are algebraic integers in $K$. We prove numerous bounding and integrality lemmas (`isIntegral_c₁α`, `isInt_β_bound`, etc.). 4. Formalizes the core algebraic coefficients $(a+b\beta)^k \alpha^{al} \gamma^{bl}$ which appear in the evaluation of the derivatives of the auxiliary function $R(x)$. 5. By scaling the system by $c_1^{n-1+2mq}$, we successfully restrict the entries of our linear system matrix `A` entirely to the ring of integers $\mathcal{O}_K$, preparing it for the application of Siegel's lemma. 6. House Bounds (`c₂`) : Establishes the foundational base integer $c_2$ to bound the absolute values of the conjugates (houses) of our coefficients. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-number-theory new-contributor awaiting-author	1002/48	Mathlib.lean,Mathlib/NumberTheory/NumberField/House.lean,Mathlib/NumberTheory/Transcendental/GelfondSchneider/MainAlg.lean,Mathlib/RingTheory/Algebraic/NatDenominator.lean,Mathlib/RingTheory/IntegralClosure/Algebra/Basic.lean,scripts/open_gelfond_schneider_prs.sh	6	26	['MichaelStollBayreuth', 'github-actions', 'mathlib-merge-conflicts', 'mkaratarakis', 'tb65536']	tb65536 assignee:tb65536	7-2156 7 days ago	8-10101 8 days ago	47-15598 47 days
36763	alok author:alok	refactor(Order/Filter/Germ): partial sections for Filter.Product	## Summary - Refactor `Filter.Product` from total functions to partial sections (`Product.Section`) with filter-large domains - Adapt the model-theoretic `Prestructure` and Łoś's theorem proofs to partial sections - Add `Germ ↔ Product` bridge equivalence for constant families ## Motivation The current `Filter.Product` is a quotient of total functions `(a : α) → ε a` by eventual equality. This requires all fibers to be inhabited, which is not the mathematically correct construction. The ultraproduct should only require a section defined on a filter-large set. The new `Product.Section` structure carries: - A domain `dom : Set α` with `dom ∈ l` - A dependent section `val : (a : dom) → ε a` Two sections are equivalent if they agree on some filter-large common domain. This matches the standard mathematical construction and enables proper ultraproducts where some fibers may be empty. ## Changes ### `Mathlib/Order/Filter/Germ/Basic.lean` - New `Product.Section` structure (partial section with filter-large domain) - `productSetoid` redefined over `Product.Section` - `Product.ofTotal` embeds total sections; `eq_iff_ofTotal` characterizes equality ### `Mathlib/ModelTheory/Ultraproducts.lean` - `sectionStructure`: first-order structure on partial sections (funMap restricts to domain intersection, RelMap checks on common domain) - `setoidPrestructure` adapted with full proofs of `fun_equiv` and `rel_equiv` - `funMap_cast`, `boundedFormula_realize_cast` (rel case), `all` quantifier case all reproved for partial sections - Łoś's theorem statement unchanged; `sentence_realize` still has the same API ### `Mathlib/Order/Filter/Germ/Product.lean` (new) - `Germ.toProduct` / `Product.toGerm`: round-trip between germs and constant-family products - `Germ.prodEquiv`: equivalence for inhabited constant families (backward compat) ## Test plan - [x] `lake build` passes (7607/7607 modules) - [x] All linter warnings resolved - [x] `Mathlib.ModelTheory.Satisfiability` (uses `Filter.Product` + `sentence_realize`) still compiles - [x] `Mathlib.Analysis.Real.Hyperreal` still compiles --- Context: [Zulip discussion](https://leanprover.zulipchat.com/#narrow/channel/217875-Is-there-code-for-X.3F/topic/Nonstandard.20Analysis/near/513178715) — Violeta Hernández asked for fixing the ultraproduct definition as the first step after #33650 deprecated the old hyperreal machinery. 🤖 Generated with [Claude Code](https://claude.com/claude-code)	new-contributor merge-conflict	278/49	Mathlib.lean,Mathlib/ModelTheory/Ultraproducts.lean,Mathlib/Order/Filter/Germ/Basic.lean,Mathlib/Order/Filter/Germ/Product.lean	4	6	['alok', 'github-actions', 'mathlib-merge-conflicts', 'plp127']	nobody	7-303 7 days ago	unknown	unknown

Stale delegated PRs

Number	Author	Title	Description	Labels	+/-	Modified files (first 100)	📝	💬	All users who commented or reviewed	Assignee(s)	Updated	Last status change	total time in review
25765	JovanGerb author:JovanGerb	feat(gcongr): lemma for rewriting inside divisibility	TODO: add test to show that we can rewrite using `a ≡ b [ZMOD n]` inside `n ∣ 2 * a + 1`. edit: it's not yet entirely clear if this is the right thing to do. edit: This lemma should be written using iff (or =), so that we can use it specifically when rewriting with a symmetric relation. Supporting equality in `gcongr` is still work in progress. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	delegated t-data	5/0	Mathlib/Data/Int/ModEq.lean	1	3	['fpvandoorn', 'github-actions', 'mathlib-bors']	nobody	200-14992 6 months ago	unknown	unknown
35588	eric-wieser author:eric-wieser	chore(Util/Qq): remove `meta`	These are wrappers of existing functions on `Expr`s which are also not marked `meta`. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-meta awaiting-CI delegated	7/7	Mathlib/Data/Multiset/Sort.lean,Mathlib/Tactic/FieldSimp/Lemmas.lean,Mathlib/Tactic/NormNum/Core.lean,Mathlib/Tactic/Order/ToInt.lean,Mathlib/Tactic/Simproc/Divisors.lean,Mathlib/Tactic/Simproc/FinsetInterval.lean,Mathlib/Util/Qq.lean	7	3	['Vierkantor', 'github-actions', 'mathlib-bors']	nobody	83-27845 2 months ago	unknown	unknown
38702	jcommelin author:jcommelin	chore(Data/Real): encapsulate real numbers	This PR: * hides the definition of the real numbers * preserves defeqs when casting `Nat`, `Int`, `Rat`, into the reals * preserves the defeq `x - y = x + (-y)` for `x y : Real` * removes a bunch of technical debt * adjusts imports in the library, where files relied on getting access to Cauchy sequences transitively via importing the reals. --- [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	delegated merge-conflict	235/256	Archive/Imo/Imo2013Q5.lean,Counterexamples/SeminormLatticeNotDistrib.lean,Mathlib.lean,Mathlib/Analysis/Complex/Norm.lean,Mathlib/Analysis/RCLike/Basic.lean,Mathlib/Analysis/Real/Cardinality.lean,Mathlib/Combinatorics/SimpleGraph/Triangle/Counting.lean,Mathlib/Data/Complex/Basic.lean,Mathlib/Data/ENNReal/Basic.lean,Mathlib/Data/NNReal/Defs.lean,Mathlib/Data/Real/Archimedean.lean,Mathlib/Data/Real/Basic.lean,Mathlib/Data/Real/Cauchy.lean,Mathlib/Data/Real/Sign.lean,Mathlib/NumberTheory/Padics/PadicIntegers.lean,Mathlib/NumberTheory/Padics/PadicNumbers.lean,Mathlib/NumberTheory/SelbergSieve.lean,Mathlib/Topology/Algebra/Ring/Real.lean,Mathlib/Topology/Instances/Real/Lemmas.lean,Mathlib/Topology/MetricSpace/CauSeqFilter.lean,Mathlib/Topology/UniformSpace/CompareReals.lean,Mathlib/Topology/UniformSpace/Real.lean,MathlibTest/Complex.lean,MathlibTest/Quaternion.lean,MathlibTest/Real.lean,MathlibTest/peel.lean	26	32	['JovanGerb', 'Kha', 'YaelDillies', 'eric-wieser', 'fpvandoorn', 'github-actions', 'jcommelin', 'leanprover-radar', 'mathlib-bors', 'mathlib-merge-conflicts', 'riccardobrasca', 'sgouezel', 'wkrozowski']	nobody	9-76408 9 days ago	unknown	unknown
37642	SnirBroshi author:SnirBroshi	chore(Combinatorics/SimpleGraph): tidy various files	--- Concept inspired by @Ruben-VandeVelde :) [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)	t-combinatorics delegated	73/62	Mathlib/Combinatorics/SimpleGraph/Coloring/VertexColoring.lean,Mathlib/Combinatorics/SimpleGraph/Copy.lean,Mathlib/Combinatorics/SimpleGraph/Extremal/Basic.lean,Mathlib/Combinatorics/SimpleGraph/IncMatrix.lean,Mathlib/Combinatorics/SimpleGraph/Maps.lean,Mathlib/Combinatorics/SimpleGraph/Trails.lean,Mathlib/Combinatorics/SimpleGraph/Walk/Decomp.lean,Mathlib/Combinatorics/SimpleGraph/Walk/Operations.lean,Mathlib/Combinatorics/SimpleGraph/Walk/Subwalks.lean	9	15	['SnirBroshi', 'YaelDillies', 'b-mehta', 'github-actions', 'mathlib-bors', 'mathlib-merge-conflicts']	nobody	1-48487 1 day ago	1-68940 1 day ago	55-19199 55 days