Documentation

Mathlib.RingTheory.NonUnitalSubsemiring.Basic

Bundled non-unital subsemirings #

We define the CompleteLattice structure, and non-unital subsemiring map, comap and range (srange) of a NonUnitalRingHom etc.

theorem NonUnitalSubsemiring.toSubsemigroup_mono {R : Type u} [NonUnitalNonAssocSemiring R] :
Monotone NonUnitalSubsemiring.toSubsemigroup
theorem NonUnitalSubsemiring.toAddSubmonoid_mono {R : Type u} [NonUnitalNonAssocSemiring R] :
Monotone NonUnitalSubsemiring.toAddSubmonoid

The ring equiv between the top element of NonUnitalSubsemiring R and R.

Equations
  • NonUnitalSubsemiring.topEquiv = { toEquiv := Subsemigroup.topEquiv.toEquiv, map_mul' := , map_add' := }
Instances For
    @[simp]
    theorem NonUnitalSubsemiring.topEquiv_symm_apply_coe {R : Type u} [NonUnitalNonAssocSemiring R] (x : R) :
    (NonUnitalSubsemiring.topEquiv.symm x) = x
    @[simp]
    theorem NonUnitalSubsemiring.topEquiv_apply {R : Type u} [NonUnitalNonAssocSemiring R] (x : ) :
    NonUnitalSubsemiring.topEquiv x = x

    The preimage of a non-unital subsemiring along a non-unital ring homomorphism is a non-unital subsemiring.

    Equations
    Instances For

      The image of a non-unital subsemiring along a ring homomorphism is a non-unital subsemiring.

      Equations
      Instances For
        @[simp]
        theorem NonUnitalSubsemiring.mem_map {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] {f : F} {s : NonUnitalSubsemiring R} {y : S} :
        y NonUnitalSubsemiring.map f s xs, f x = y

        A non-unital subsemiring is isomorphic to its image under an injective function

        Equations
        • s.equivMapOfInjective f hf = { toEquiv := Equiv.Set.image (⇑f) (↑s) hf, map_mul' := , map_add' := }
        Instances For
          @[simp]
          theorem NonUnitalSubsemiring.coe_equivMapOfInjective_apply {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] (s : NonUnitalSubsemiring R) (f : F) (hf : Function.Injective f) (x : s) :
          ((s.equivMapOfInjective f hf) x) = f x

          The range of a non-unital ring homomorphism is a non-unital subsemiring. See note [range copy pattern].

          Equations
          Instances For
            @[simp]
            theorem NonUnitalRingHom.mem_srange {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] {f : F} {y : S} :
            y NonUnitalRingHom.srange f ∃ (x : R), f x = y

            The range of a morphism of non-unital semirings is finite if the domain is a finite.

            Equations
            • =
            Equations
            @[simp]
            theorem NonUnitalSubsemiring.coe_sInf {R : Type u} [NonUnitalNonAssocSemiring R] (S : Set (NonUnitalSubsemiring R)) :
            (sInf S) = sS, s
            theorem NonUnitalSubsemiring.mem_sInf {R : Type u} [NonUnitalNonAssocSemiring R] {S : Set (NonUnitalSubsemiring R)} {x : R} :
            x sInf S pS, x p
            @[simp]
            theorem NonUnitalSubsemiring.coe_iInf {R : Type u} [NonUnitalNonAssocSemiring R] {ι : Sort u_1} {S : ιNonUnitalSubsemiring R} :
            (⨅ (i : ι), S i) = ⋂ (i : ι), (S i)
            theorem NonUnitalSubsemiring.mem_iInf {R : Type u} [NonUnitalNonAssocSemiring R] {ι : Sort u_1} {S : ιNonUnitalSubsemiring R} {x : R} :
            x ⨅ (i : ι), S i ∀ (i : ι), x S i
            @[simp]
            theorem NonUnitalSubsemiring.sInf_toSubsemigroup {R : Type u} [NonUnitalNonAssocSemiring R] (s : Set (NonUnitalSubsemiring R)) :
            (sInf s).toSubsemigroup = ts, t.toSubsemigroup
            @[simp]
            theorem NonUnitalSubsemiring.sInf_toAddSubmonoid {R : Type u} [NonUnitalNonAssocSemiring R] (s : Set (NonUnitalSubsemiring R)) :
            (sInf s).toAddSubmonoid = ts, t.toAddSubmonoid

            Non-unital subsemirings of a non-unital semiring form a complete lattice.

            Equations

            The center of a semiring R is the set of elements that commute and associate with everything in R

            Equations
            Instances For
              theorem Set.mem_center_iff_addMonoidHom (R : Type u) [NonUnitalNonAssocSemiring R] (a : R) :
              a Set.center R AddMonoidHom.mulLeft a = AddMonoidHom.mulRight a AddMonoidHom.mul.compr₂ (AddMonoidHom.mulLeft a) = AddMonoidHom.mul.comp (AddMonoidHom.mulLeft a) AddMonoidHom.mul.comp (AddMonoidHom.mulRight a) = AddMonoidHom.mul.compl₂ (AddMonoidHom.mulLeft a) AddMonoidHom.mul.compr₂ (AddMonoidHom.mulRight a) = AddMonoidHom.mul.compl₂ (AddMonoidHom.mulRight a)

              A point-free means of proving membership in the center, for a non-associative ring.

              This can be helpful when working with types that have ext lemmas for R →+ R.

              The centralizer of a set as non-unital subsemiring.

              Equations
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                @[simp]

                The non-unital subsemiring generated by a set includes the set.

                @[simp]

                A non-unital subsemiring S includes closure s if and only if it includes s.

                Subsemiring closure of a set is monotone in its argument: if s ⊆ t, then closure s ≤ closure t.

                @[reducible, inline]
                abbrev NonUnitalSubsemiring.closureNonUnitalCommSemiringOfComm {R : Type u_1} [NonUnitalSemiring R] {s : Set R} (hcomm : xs, ys, x * y = y * x) :

                If all the elements of a set s commute, then closure s is a non-unital commutative semiring.

                Equations
                Instances For

                  The additive closure of a non-unital subsemigroup is a non-unital subsemiring.

                  Equations
                  Instances For
                    theorem Subsemigroup.nonUnitalSubsemiringClosure_coe {R : Type u} [NonUnitalNonAssocSemiring R] (M : Subsemigroup R) :
                    M.nonUnitalSubsemiringClosure = (AddSubmonoid.closure M)
                    theorem Subsemigroup.nonUnitalSubsemiringClosure_toAddSubmonoid {R : Type u} [NonUnitalNonAssocSemiring R] (M : Subsemigroup R) :
                    M.nonUnitalSubsemiringClosure.toAddSubmonoid = AddSubmonoid.closure M

                    The NonUnitalSubsemiring generated by a multiplicative subsemigroup coincides with the NonUnitalSubsemiring.closure of the subsemigroup itself .

                    The elements of the non-unital subsemiring closure of M are exactly the elements of the additive closure of a multiplicative subsemigroup M.

                    theorem NonUnitalSubsemiring.closure_induction {R : Type u} [NonUnitalNonAssocSemiring R] {s : Set R} {p : (x : R) → x NonUnitalSubsemiring.closure sProp} (mem : ∀ (x : R) (hx : x s), p x ) (zero : p 0 ) (add : ∀ (x y : R) (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s), p x hxp y hyp (x + y) ) (mul : ∀ (x y : R) (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s), p x hxp y hyp (x * y) ) {x : R} (hx : x NonUnitalSubsemiring.closure s) :
                    p x hx

                    An induction principle for closure membership. If p holds for 0, 1, and all elements of s, and is preserved under addition and multiplication, then p holds for all elements of the closure of s.

                    theorem NonUnitalSubsemiring.closure_induction₂ {R : Type u} [NonUnitalNonAssocSemiring R] {s : Set R} {p : (x y : R) → x NonUnitalSubsemiring.closure sy NonUnitalSubsemiring.closure sProp} (mem_mem : ∀ (x : R) (hx : x s) (y : R) (hy : y s), p x y ) (zero_left : ∀ (x : R) (hx : x NonUnitalSubsemiring.closure s), p 0 x hx) (zero_right : ∀ (x : R) (hx : x NonUnitalSubsemiring.closure s), p x 0 hx ) (add_left : ∀ (x y z : R) (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s) (hz : z NonUnitalSubsemiring.closure s), p x z hx hzp y z hy hzp (x + y) z hz) (add_right : ∀ (x y z : R) (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s) (hz : z NonUnitalSubsemiring.closure s), p x y hx hyp x z hx hzp x (y + z) hx ) (mul_left : ∀ (x y z : R) (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s) (hz : z NonUnitalSubsemiring.closure s), p x z hx hzp y z hy hzp (x * y) z hz) (mul_right : ∀ (x y z : R) (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s) (hz : z NonUnitalSubsemiring.closure s), p x y hx hyp x z hx hzp x (y * z) hx ) {x y : R} (hx : x NonUnitalSubsemiring.closure s) (hy : y NonUnitalSubsemiring.closure s) :
                    p x y hx hy

                    An induction principle for closure membership for predicates with two arguments.

                    def NonUnitalSubsemiring.gi (R : Type u) [NonUnitalNonAssocSemiring R] :
                    GaloisInsertion NonUnitalSubsemiring.closure SetLike.coe

                    closure forms a Galois insertion with the coercion to set.

                    Equations
                    Instances For

                      Closure of a non-unital subsemiring S equals S.

                      theorem NonUnitalSubsemiring.closure_iUnion {R : Type u} [NonUnitalNonAssocSemiring R] {ι : Sort u_2} (s : ιSet R) :
                      NonUnitalSubsemiring.closure (⋃ (i : ι), s i) = ⨆ (i : ι), NonUnitalSubsemiring.closure (s i)
                      theorem NonUnitalSubsemiring.map_iInf {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] {ι : Sort u_2} [Nonempty ι] (f : F) (hf : Function.Injective f) (s : ιNonUnitalSubsemiring R) :

                      Given NonUnitalSubsemirings s, t of semirings R, S respectively, s.prod t is s × t as a non-unital subsemiring of R × S.

                      Equations
                      • s.prod t = { carrier := s ×ˢ t, add_mem' := , zero_mem' := , mul_mem' := }
                      Instances For
                        theorem NonUnitalSubsemiring.prod_mono {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] ⦃s₁ s₂ : NonUnitalSubsemiring R (hs : s₁ s₂) ⦃t₁ t₂ : NonUnitalSubsemiring S (ht : t₁ t₂) :
                        s₁.prod t₁ s₂.prod t₂

                        Product of non-unital subsemirings is isomorphic to their product as semigroups.

                        Equations
                        • s.prodEquiv t = { toEquiv := Equiv.Set.prod s t, map_mul' := , map_add' := }
                        Instances For
                          theorem NonUnitalSubsemiring.mem_iSup_of_directed {R : Type u} [NonUnitalNonAssocSemiring R] {ι : Sort u_2} [hι : Nonempty ι] {S : ιNonUnitalSubsemiring R} (hS : Directed (fun (x1 x2 : NonUnitalSubsemiring R) => x1 x2) S) {x : R} :
                          x ⨆ (i : ι), S i ∃ (i : ι), x S i
                          theorem NonUnitalSubsemiring.coe_iSup_of_directed {R : Type u} [NonUnitalNonAssocSemiring R] {ι : Sort u_2} [hι : Nonempty ι] {S : ιNonUnitalSubsemiring R} (hS : Directed (fun (x1 x2 : NonUnitalSubsemiring R) => x1 x2) S) :
                          (⨆ (i : ι), S i) = ⋃ (i : ι), (S i)
                          theorem NonUnitalSubsemiring.mem_sSup_of_directedOn {R : Type u} [NonUnitalNonAssocSemiring R] {S : Set (NonUnitalSubsemiring R)} (Sne : S.Nonempty) (hS : DirectedOn (fun (x1 x2 : NonUnitalSubsemiring R) => x1 x2) S) {x : R} :
                          x sSup S sS, x s
                          theorem NonUnitalSubsemiring.coe_sSup_of_directedOn {R : Type u} [NonUnitalNonAssocSemiring R] {S : Set (NonUnitalSubsemiring R)} (Sne : S.Nonempty) (hS : DirectedOn (fun (x1 x2 : NonUnitalSubsemiring R) => x1 x2) S) :
                          (sSup S) = sS, s
                          theorem NonUnitalRingHom.eq_of_eqOn_stop {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] {F : Type u_1} [FunLike F R S] {f g : F} (h : Set.EqOn f g ) :
                          f = g

                          Restriction of a non-unital ring homomorphism to its range interpreted as a non-unital subsemiring.

                          This is the bundled version of Set.rangeFactorization.

                          Equations
                          Instances For
                            @[deprecated NonUnitalRingHom.srange_eq_top_iff_surjective]

                            Alias of NonUnitalRingHom.srange_eq_top_iff_surjective.

                            @[simp]

                            The range of a surjective non-unital ring homomorphism is the whole of the codomain.

                            @[deprecated NonUnitalRingHom.srange_eq_top_of_surjective]

                            Alias of NonUnitalRingHom.srange_eq_top_of_surjective.


                            The range of a surjective non-unital ring homomorphism is the whole of the codomain.

                            theorem NonUnitalRingHom.eqOn_sclosure {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] {F : Type u_1} [FunLike F R S] [NonUnitalNonAssocSemiring S] [NonUnitalRingHomClass F R S] {f g : F} {s : Set R} (h : Set.EqOn (⇑f) (⇑g) s) :

                            If two non-unital ring homomorphisms are equal on a set, then they are equal on its non-unital subsemiring closure.

                            theorem NonUnitalRingHom.eq_of_eqOn_sdense {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] {F : Type u_1} [FunLike F R S] [NonUnitalNonAssocSemiring S] [NonUnitalRingHomClass F R S] {s : Set R} (hs : NonUnitalSubsemiring.closure s = ) {f g : F} (h : Set.EqOn (⇑f) (⇑g) s) :
                            f = g

                            The image under a ring homomorphism of the subsemiring generated by a set equals the subsemiring generated by the image of the set.

                            Makes the identity isomorphism from a proof two non-unital subsemirings of a multiplicative monoid are equal.

                            Equations
                            Instances For
                              def RingEquiv.sofLeftInverse' {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] {g : SR} {f : F} (h : Function.LeftInverse g f) :

                              Restrict a non-unital ring homomorphism with a left inverse to a ring isomorphism to its NonUnitalRingHom.srange.

                              Equations
                              • One or more equations did not get rendered due to their size.
                              Instances For
                                @[simp]
                                theorem RingEquiv.sofLeftInverse'_apply {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] {g : SR} {f : F} (h : Function.LeftInverse g f) (x : R) :
                                @[simp]
                                theorem RingEquiv.sofLeftInverse'_symm_apply {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] {F : Type u_1} [FunLike F R S] [NonUnitalRingHomClass F R S] {g : SR} {f : F} (h : Function.LeftInverse g f) (x : (NonUnitalRingHom.srange f)) :
                                (RingEquiv.sofLeftInverse' h).symm x = g x

                                Given an equivalence e : R ≃+* S of non-unital semirings and a non-unital subsemiring s of R, non_unital_subsemiring_map e s is the induced equivalence between s and s.map e

                                Equations
                                • e.nonUnitalSubsemiringMap s = { toEquiv := (e.toAddEquiv.addSubmonoidMap s.toAddSubmonoid).toEquiv, map_mul' := , map_add' := }
                                Instances For
                                  @[simp]
                                  theorem RingEquiv.nonUnitalSubsemiringMap_apply_coe {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] (e : R ≃+* S) (s : NonUnitalSubsemiring R) (x : s.toAddSubmonoid) :
                                  ((e.nonUnitalSubsemiringMap s) x) = e x
                                  @[simp]
                                  theorem RingEquiv.nonUnitalSubsemiringMap_symm_apply_coe {R : Type u} {S : Type v} [NonUnitalNonAssocSemiring R] [NonUnitalNonAssocSemiring S] (e : R ≃+* S) (s : NonUnitalSubsemiring R) (y : (e.toAddEquiv '' s.toAddSubmonoid)) :
                                  ((e.nonUnitalSubsemiringMap s).symm y) = (↑e).symm y