category_theory.connected_components | Mathlib porting status

Changes since the initial port

The following section lists changes to this file in mathlib3 and mathlib4 that occured after the initial port. Most recent changes are shown first. Hovering over a commit will show all commits associated with the same mathlib3 commit.

Changes in mathlib3

70fd9563

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

10bf4f82

bump to nightly-2024-04-14-09

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

f736ea6b

Diff

@@ -63,7 +63,7 @@ deriving Category
 @[simps (config := { rhsMd := semireducible })]
 def Component.ι (j) : Component j ⥤ J :=
   fullSubcategoryInclusion _
-deriving Full, Faithful
+deriving CategoryTheory.Functor.Full, CategoryTheory.Functor.Faithful
 #align category_theory.component.ι CategoryTheory.Component.ι
 -/
 
@@ -140,7 +140,7 @@ theorem inclusion_comp_decomposedTo (j : ConnectedComponents J) :
 #align category_theory.inclusion_comp_decomposed_to CategoryTheory.inclusion_comp_decomposedTo
 -/
 
-instance : Full (decomposedTo J)
+instance : CategoryTheory.Functor.Full (decomposedTo J)
     where
   Preimage := by
     rintro ⟨j', X, hX⟩ ⟨k', Y, hY⟩ f
@@ -158,16 +158,17 @@ instance : Full (decomposedTo J)
     subst this
     rfl
 
-instance : Faithful (decomposedTo J)
+instance : CategoryTheory.Functor.Faithful (decomposedTo J)
     where map_injective' := by
     rintro ⟨_, j, rfl⟩ ⟨_, k, hY⟩ ⟨f⟩ ⟨g⟩ e
     change f = g at e
     subst e
 
-instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩, ⟨Iso.refl _⟩⟩
+instance : CategoryTheory.Functor.EssSurj (decomposedTo J)
+    where mem_essImage j := ⟨⟨_, j, rfl⟩, ⟨Iso.refl _⟩⟩
 
-instance : IsEquivalence (decomposedTo J) :=
-  Equivalence.ofFullyFaithfullyEssSurj _
+instance : CategoryTheory.Functor.IsEquivalence (decomposedTo J) :=
+  CategoryTheory.Functor.IsEquivalence.ofFullyFaithfullyEssSurj _
 
 #print CategoryTheory.decomposedEquiv /-
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/

10bf4f82

bump to nightly-2024-03-17-08

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

22f01ce4

Diff

@@ -144,7 +144,7 @@ instance : Full (decomposedTo J)
     where
   Preimage := by
     rintro ⟨j', X, hX⟩ ⟨k', Y, hY⟩ f
-    dsimp at f 
+    dsimp at f
     have : j' = k'
     rw [← hX, ← hY, Quotient.eq'']
     exact Relation.ReflTransGen.single (Or.inl ⟨f⟩)
@@ -161,7 +161,7 @@ instance : Full (decomposedTo J)
 instance : Faithful (decomposedTo J)
     where map_injective' := by
     rintro ⟨_, j, rfl⟩ ⟨_, k, hY⟩ ⟨f⟩ ⟨g⟩ e
-    change f = g at e 
+    change f = g at e
     subst e
 
 instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩, ⟨Iso.refl _⟩⟩

10bf4f82

bump to nightly-2023-09-24-06

mathlib commit https://github.com/leanprover-community/mathlib/commit/ce64cd319bb6b3e82f31c2d38e79080d377be451

5655435f

Diff

@@ -3,10 +3,10 @@ Copyright (c) 2020 Bhavik Mehta. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Bhavik Mehta
 -/
-import Mathbin.Data.List.Chain
-import Mathbin.CategoryTheory.IsConnected
-import Mathbin.CategoryTheory.Sigma.Basic
-import Mathbin.CategoryTheory.FullSubcategory
+import Data.List.Chain
+import CategoryTheory.IsConnected
+import CategoryTheory.Sigma.Basic
+import CategoryTheory.FullSubcategory
 
 #align_import category_theory.connected_components from "leanprover-community/mathlib"@"10bf4f825ad729c5653adc039dafa3622e7f93c9"

10bf4f82

bump to nightly-2023-07-20-09

mathlib commit https://github.com/leanprover-community/mathlib/commit/8ea5598db6caeddde6cb734aa179cc2408dbd345

9c56d0dd

Diff

@@ -2,17 +2,14 @@
 Copyright (c) 2020 Bhavik Mehta. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Bhavik Mehta
-
-! This file was ported from Lean 3 source module category_theory.connected_components
-! leanprover-community/mathlib commit 10bf4f825ad729c5653adc039dafa3622e7f93c9
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Data.List.Chain
 import Mathbin.CategoryTheory.IsConnected
 import Mathbin.CategoryTheory.Sigma.Basic
 import Mathbin.CategoryTheory.FullSubcategory
 
+#align_import category_theory.connected_components from "leanprover-community/mathlib"@"10bf4f825ad729c5653adc039dafa3622e7f93c9"
+
 /-!
 # Connected components of a category

10bf4f82

bump to nightly-2023-06-13-21

mathlib commit https://github.com/leanprover-community/mathlib/commit/9fb8964792b4237dac6200193a0d533f1b3f7423

829520ac

Diff

@@ -61,12 +61,14 @@ deriving Category
 #align category_theory.component CategoryTheory.Component
 -/
 
+#print CategoryTheory.Component.ι /-
 /-- The inclusion functor from a connected component to the whole category. -/
 @[simps (config := { rhsMd := semireducible })]
 def Component.ι (j) : Component j ⥤ J :=
   fullSubcategoryInclusion _
 deriving Full, Faithful
 #align category_theory.component.ι CategoryTheory.Component.ι
+-/
 
 /-- Each connected component of the category is nonempty. -/
 instance (j : ConnectedComponents J) : Nonempty (Component j) :=
@@ -170,11 +172,13 @@ instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩,
 instance : IsEquivalence (decomposedTo J) :=
   Equivalence.ofFullyFaithfullyEssSurj _
 
+#print CategoryTheory.decomposedEquiv /-
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/
 @[simps (config := { rhsMd := semireducible }) Functor]
 def decomposedEquiv : Decomposed J ≌ J :=
   (decomposedTo J).asEquivalence
 #align category_theory.decomposed_equiv CategoryTheory.decomposedEquiv
+-/
 
 end CategoryTheory

10bf4f82

bump to nightly-2023-06-01-16

mathlib commit https://github.com/leanprover-community/mathlib/commit/cca40788df1b8755d5baf17ab2f27dacc2e17acb

b9c87c70

Diff

@@ -56,14 +56,16 @@ instance [Inhabited J] : Inhabited (ConnectedComponents J) :=
 #print CategoryTheory.Component /-
 /-- Given an index for a connected component, produce the actual component as a full subcategory. -/
 def Component (j : ConnectedComponents J) : Type u₁ :=
-  FullSubcategory fun k => Quotient.mk'' k = j deriving Category
+  FullSubcategory fun k => Quotient.mk'' k = j
+deriving Category
 #align category_theory.component CategoryTheory.Component
 -/
 
 /-- The inclusion functor from a connected component to the whole category. -/
 @[simps (config := { rhsMd := semireducible })]
 def Component.ι (j) : Component j ⥤ J :=
-  fullSubcategoryInclusion _ deriving Full, Faithful
+  fullSubcategoryInclusion _
+deriving Full, Faithful
 #align category_theory.component.ι CategoryTheory.Component.ι
 
 /-- Each connected component of the category is nonempty. -/
@@ -108,7 +110,7 @@ category structure.
 This category is equivalent to `J`.
 -/
 abbrev Decomposed (J : Type u₁) [Category.{v₁} J] :=
-  Σj : ConnectedComponents J, Component j
+  Σ j : ConnectedComponents J, Component j
 #align category_theory.decomposed CategoryTheory.Decomposed
 -/
 
@@ -143,7 +145,7 @@ instance : Full (decomposedTo J)
     where
   Preimage := by
     rintro ⟨j', X, hX⟩ ⟨k', Y, hY⟩ f
-    dsimp at f
+    dsimp at f 
     have : j' = k'
     rw [← hX, ← hY, Quotient.eq'']
     exact Relation.ReflTransGen.single (Or.inl ⟨f⟩)
@@ -160,7 +162,7 @@ instance : Full (decomposedTo J)
 instance : Faithful (decomposedTo J)
     where map_injective' := by
     rintro ⟨_, j, rfl⟩ ⟨_, k, hY⟩ ⟨f⟩ ⟨g⟩ e
-    change f = g at e
+    change f = g at e 
     subst e
 
 instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩, ⟨Iso.refl _⟩⟩

10bf4f82

bump to nightly-2023-05-28-06

mathlib commit https://github.com/leanprover-community/mathlib/commit/917c3c072e487b3cccdbfeff17e75b40e45f66cb

ba5d8b97

Diff

@@ -60,12 +60,6 @@ def Component (j : ConnectedComponents J) : Type u₁ :=
 #align category_theory.component CategoryTheory.Component
 -/
 
-/- warning: category_theory.component.ι -> CategoryTheory.Component.ι is a dubious translation:
-lean 3 declaration is
-  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J] (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1), CategoryTheory.Functor.{u1, u1, u2, u2} (CategoryTheory.Component.{u1, u2} J _inst_1 j) (CategoryTheory.InducedCategory.category.{u1, u2, u2} (CategoryTheory.FullSubcategoryₓ.{u1, u2} J _inst_1 (fun (k : J) => Eq.{succ u2} (Quotient.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1)) (Quotient.mk''.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1) k) j)) J _inst_1 (CategoryTheory.FullSubcategoryₓ.obj.{u1, u2} J _inst_1 (fun (k : J) => Eq.{succ u2} (Quotient.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1)) (Quotient.mk''.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1) k) j))) J _inst_1
-but is expected to have type
-  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J] (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1), CategoryTheory.Functor.{u1, u1, u2, u2} (CategoryTheory.Component.{u1, u2} J _inst_1 j) (CategoryTheory.instCategoryComponent.{u1, u2} J _inst_1 j) J _inst_1
-Case conversion may be inaccurate. Consider using '#align category_theory.component.ι CategoryTheory.Component.ιₓ'. -/
 /-- The inclusion functor from a connected component to the whole category. -/
 @[simps (config := { rhsMd := semireducible })]
 def Component.ι (j) : Component j ⥤ J :=
@@ -174,12 +168,6 @@ instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩,
 instance : IsEquivalence (decomposedTo J) :=
   Equivalence.ofFullyFaithfullyEssSurj _
 
-/- warning: category_theory.decomposed_equiv -> CategoryTheory.decomposedEquiv is a dubious translation:
-lean 3 declaration is
-  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J], CategoryTheory.Equivalence.{max u1 u2, u1, u2, u2} (CategoryTheory.Decomposed.{u1, u2} J _inst_1) (CategoryTheory.Sigma.sigma.{u2, u1, u2} (CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) (fun (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.Component.{u1, u2} J _inst_1 j) (fun (i : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.Component.category.{u2, u1} J _inst_1 i)) J _inst_1
-but is expected to have type
-  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J], CategoryTheory.Equivalence.{max u2 u1, u1, u2, u2} (CategoryTheory.Decomposed.{u1, u2} J _inst_1) J (CategoryTheory.Sigma.sigma.{u2, u1, u2} (CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) (fun (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.Component.{u1, u2} J _inst_1 j) (fun (i : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.instCategoryComponent.{u1, u2} J _inst_1 i)) _inst_1
-Case conversion may be inaccurate. Consider using '#align category_theory.decomposed_equiv CategoryTheory.decomposedEquivₓ'. -/
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/
 @[simps (config := { rhsMd := semireducible }) Functor]
 def decomposedEquiv : Decomposed J ≌ J :=

10bf4f82

bump to nightly-2023-04-24-06

mathlib commit https://github.com/leanprover-community/mathlib/commit/09079525fd01b3dda35e96adaa08d2f943e1648c

ff662d55

Diff

@@ -37,7 +37,7 @@ open CategoryTheory.Category
 
 namespace CategoryTheory
 
-attribute [instance] is_connected.is_nonempty
+attribute [instance 100] is_connected.is_nonempty
 
 variable {J : Type u₁} [Category.{v₁} J]

10bf4f82

bump to nightly-2023-03-16-03

mathlib commit https://github.com/leanprover-community/mathlib/commit/ce7e9d53d4bbc38065db3b595cd5bd73c323bc1d

8ae28b0b

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Bhavik Mehta
 
 ! This file was ported from Lean 3 source module category_theory.connected_components
-! leanprover-community/mathlib commit 70fd9563a21e7b963887c9360bd29b2393e6225a
+! leanprover-community/mathlib commit 10bf4f825ad729c5653adc039dafa3622e7f93c9
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -16,6 +16,9 @@ import Mathbin.CategoryTheory.FullSubcategory
 /-!
 # Connected components of a category
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 Defines a type `connected_components J` indexing the connected components of a category, and the
 full subcategories giving each connected component: `component j : Type u₁`.
 We show that each `component j` is in fact connected.

70fd9563

bump to nightly-2023-03-13-14

mathlib commit https://github.com/leanprover-community/mathlib/commit/2af0836443b4cfb5feda0df0051acdb398304931

a0c9db6f

Diff

@@ -40,19 +40,29 @@ variable {J : Type u₁} [Category.{v₁} J]
 
 variable {C : Type u₂} [Category.{u₁} C]
 
+#print CategoryTheory.ConnectedComponents /-
 /-- This type indexes the connected components of the category `J`. -/
 def ConnectedComponents (J : Type u₁) [Category.{v₁} J] : Type u₁ :=
   Quotient (Zigzag.setoid J)
 #align category_theory.connected_components CategoryTheory.ConnectedComponents
+-/
 
 instance [Inhabited J] : Inhabited (ConnectedComponents J) :=
   ⟨Quotient.mk'' default⟩
 
+#print CategoryTheory.Component /-
 /-- Given an index for a connected component, produce the actual component as a full subcategory. -/
 def Component (j : ConnectedComponents J) : Type u₁ :=
   FullSubcategory fun k => Quotient.mk'' k = j deriving Category
 #align category_theory.component CategoryTheory.Component
+-/
 
+/- warning: category_theory.component.ι -> CategoryTheory.Component.ι is a dubious translation:
+lean 3 declaration is
+  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J] (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1), CategoryTheory.Functor.{u1, u1, u2, u2} (CategoryTheory.Component.{u1, u2} J _inst_1 j) (CategoryTheory.InducedCategory.category.{u1, u2, u2} (CategoryTheory.FullSubcategoryₓ.{u1, u2} J _inst_1 (fun (k : J) => Eq.{succ u2} (Quotient.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1)) (Quotient.mk''.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1) k) j)) J _inst_1 (CategoryTheory.FullSubcategoryₓ.obj.{u1, u2} J _inst_1 (fun (k : J) => Eq.{succ u2} (Quotient.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1)) (Quotient.mk''.{succ u2} J (CategoryTheory.Zigzag.setoid.{u1, u2} J _inst_1) k) j))) J _inst_1
+but is expected to have type
+  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J] (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1), CategoryTheory.Functor.{u1, u1, u2, u2} (CategoryTheory.Component.{u1, u2} J _inst_1 j) (CategoryTheory.instCategoryComponent.{u1, u2} J _inst_1 j) J _inst_1
+Case conversion may be inaccurate. Consider using '#align category_theory.component.ι CategoryTheory.Component.ιₓ'. -/
 /-- The inclusion functor from a connected component to the whole category. -/
 @[simps (config := { rhsMd := semireducible })]
 def Component.ι (j) : Component j ⥤ J :=
@@ -95,6 +105,7 @@ instance (j : ConnectedComponents J) : IsConnected (Component j) :=
   · erw [List.getLast_pmap _ f (j₁ :: l) (by simpa [h₁₂] using hf) (List.cons_ne_nil _ _)]
     exact full_subcategory.ext _ _ hl₂
 
+#print CategoryTheory.Decomposed /-
 /-- The disjoint union of `J`s connected components, written explicitly as a sigma-type with the
 category structure.
 This category is equivalent to `J`.
@@ -102,7 +113,9 @@ This category is equivalent to `J`.
 abbrev Decomposed (J : Type u₁) [Category.{v₁} J] :=
   Σj : ConnectedComponents J, Component j
 #align category_theory.decomposed CategoryTheory.Decomposed
+-/
 
+#print CategoryTheory.inclusion /-
 -- This name may cause clashes further down the road, and so might need to be changed.
 /--
 The inclusion of each component into the decomposed category. This is just `sigma.incl` but having
@@ -111,18 +124,23 @@ this abbreviation helps guide typeclass search to get the right category instanc
 abbrev inclusion (j : ConnectedComponents J) : Component j ⥤ Decomposed J :=
   Sigma.incl _
 #align category_theory.inclusion CategoryTheory.inclusion
+-/
 
+#print CategoryTheory.decomposedTo /-
 /-- The forward direction of the equivalence between the decomposed category and the original. -/
 @[simps (config := { rhsMd := semireducible })]
 def decomposedTo (J : Type u₁) [Category.{v₁} J] : Decomposed J ⥤ J :=
   Sigma.desc Component.ι
 #align category_theory.decomposed_to CategoryTheory.decomposedTo
+-/
 
+#print CategoryTheory.inclusion_comp_decomposedTo /-
 @[simp]
 theorem inclusion_comp_decomposedTo (j : ConnectedComponents J) :
     inclusion j ⋙ decomposedTo J = Component.ι j :=
   rfl
 #align category_theory.inclusion_comp_decomposed_to CategoryTheory.inclusion_comp_decomposedTo
+-/
 
 instance : Full (decomposedTo J)
     where
@@ -153,6 +171,12 @@ instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩,
 instance : IsEquivalence (decomposedTo J) :=
   Equivalence.ofFullyFaithfullyEssSurj _
 
+/- warning: category_theory.decomposed_equiv -> CategoryTheory.decomposedEquiv is a dubious translation:
+lean 3 declaration is
+  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J], CategoryTheory.Equivalence.{max u1 u2, u1, u2, u2} (CategoryTheory.Decomposed.{u1, u2} J _inst_1) (CategoryTheory.Sigma.sigma.{u2, u1, u2} (CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) (fun (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.Component.{u1, u2} J _inst_1 j) (fun (i : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.Component.category.{u2, u1} J _inst_1 i)) J _inst_1
+but is expected to have type
+  forall {J : Type.{u2}} [_inst_1 : CategoryTheory.Category.{u1, u2} J], CategoryTheory.Equivalence.{max u2 u1, u1, u2, u2} (CategoryTheory.Decomposed.{u1, u2} J _inst_1) J (CategoryTheory.Sigma.sigma.{u2, u1, u2} (CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) (fun (j : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.Component.{u1, u2} J _inst_1 j) (fun (i : CategoryTheory.ConnectedComponents.{u1, u2} J _inst_1) => CategoryTheory.instCategoryComponent.{u1, u2} J _inst_1 i)) _inst_1
+Case conversion may be inaccurate. Consider using '#align category_theory.decomposed_equiv CategoryTheory.decomposedEquivₓ'. -/
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/
 @[simps (config := { rhsMd := semireducible }) Functor]
 def decomposedEquiv : Decomposed J ≌ J :=

70fd9563

bump to nightly-2023-02-21-16

mathlib commit https://github.com/leanprover-community/mathlib/commit/bd9851ca476957ea4549eb19b40e7b5ade9428cc

1107b979

Changes in mathlib4

mathlib3

mathlib4

70fd9563

chore(CategoryTheory): make Functor.Full a Prop (#12449)

Before this PR, Functor.Full contained the data of the preimage of maps by a full functor F. This PR makes Functor.Full a proposition. This is to prevent any diamond to appear.

The lemma Functor.image_preimage is also renamed Functor.map_preimage.

Co-authored-by: Joël Riou <37772949+joelriou@users.noreply.github.com>

ce289a0e

Diff

@@ -127,23 +127,15 @@ theorem inclusion_comp_decomposedTo (j : ConnectedComponents J) :
   rfl
 #align category_theory.inclusion_comp_decomposed_to CategoryTheory.inclusion_comp_decomposedTo
 
-instance : (decomposedTo J).Full
-    where
-  preimage := by
+instance : (decomposedTo J).Full where
+  map_surjective := by
     rintro ⟨j', X, hX⟩ ⟨k', Y, hY⟩ f
     dsimp at f
     have : j' = k' := by
       rw [← hX, ← hY, Quotient.eq'']
       exact Relation.ReflTransGen.single (Or.inl ⟨f⟩)
     subst this
-    exact Sigma.SigmaHom.mk f
-  witness := by
-    rintro ⟨j', X, hX⟩ ⟨_, Y, rfl⟩ f
-    have : Quotient.mk'' Y = j' := by
-      rw [← hX, Quotient.eq'']
-      exact Relation.ReflTransGen.single (Or.inr ⟨f⟩)
-    subst this
-    rfl
+    exact ⟨Sigma.SigmaHom.mk f, rfl⟩
 
 instance : (decomposedTo J).Faithful where
   map_injective := by

70fd9563

chore: remove autoImplicit from more files (#11798)

and reduce its scope in a few other instances. Mostly in CategoryTheory and Data this time; some Combinatorics also.

Co-authored-by: Richard Osborn <richardosborn@mac.com>

3bb1d613

Diff

@@ -48,8 +48,7 @@ def Component (j : ConnectedComponents J) : Type u₁ :=
   FullSubcategory fun k => Quotient.mk'' k = j
 #align category_theory.component CategoryTheory.Component
 
-set_option autoImplicit true in
-instance : Category (Component (j : ConnectedComponents J)) :=
+instance {j : ConnectedComponents J} : Category (Component j) :=
   FullSubcategory.category _
 
 -- Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
@@ -59,12 +58,10 @@ def Component.ι (j : ConnectedComponents J) : Component j ⥤ J :=
   fullSubcategoryInclusion _
 #align category_theory.component.ι CategoryTheory.Component.ι
 
-set_option autoImplicit true in
-instance : Functor.Full (Component.ι (j : ConnectedComponents J)) :=
+instance {j : ConnectedComponents J} : Functor.Full (Component.ι j) :=
   FullSubcategory.full _
 
-set_option autoImplicit true in
-instance : Functor.Faithful (Component.ι (j : ConnectedComponents J)) :=
+instance {j : ConnectedComponents J} : Functor.Faithful (Component.ι j) :=
   FullSubcategory.faithful _
 
 /-- Each connected component of the category is nonempty. -/

70fd9563

chore(CategoryTheory): move Full, Faithful, EssSurj, IsEquivalence and ReflectsIsomorphisms to the Functor namespace (#11985)

These notions on functors are now Functor.Full, Functor.Faithful, Functor.EssSurj, Functor.IsEquivalence, Functor.ReflectsIsomorphisms. Deprecated aliases are introduced for the previous names.

65b7affc

Diff

@@ -60,11 +60,11 @@ def Component.ι (j : ConnectedComponents J) : Component j ⥤ J :=
 #align category_theory.component.ι CategoryTheory.Component.ι
 
 set_option autoImplicit true in
-instance : Full (Component.ι (j : ConnectedComponents J)) :=
+instance : Functor.Full (Component.ι (j : ConnectedComponents J)) :=
   FullSubcategory.full _
 
 set_option autoImplicit true in
-instance : Faithful (Component.ι (j : ConnectedComponents J)) :=
+instance : Functor.Faithful (Component.ι (j : ConnectedComponents J)) :=
   FullSubcategory.faithful _
 
 /-- Each connected component of the category is nonempty. -/
@@ -130,7 +130,7 @@ theorem inclusion_comp_decomposedTo (j : ConnectedComponents J) :
   rfl
 #align category_theory.inclusion_comp_decomposed_to CategoryTheory.inclusion_comp_decomposedTo
 
-instance : Full (decomposedTo J)
+instance : (decomposedTo J).Full
     where
   preimage := by
     rintro ⟨j', X, hX⟩ ⟨k', Y, hY⟩ f
@@ -148,15 +148,15 @@ instance : Full (decomposedTo J)
     subst this
     rfl
 
-instance : Faithful (decomposedTo J) where
+instance : (decomposedTo J).Faithful where
   map_injective := by
     rintro ⟨_, j, rfl⟩ ⟨_, k, hY⟩ ⟨f⟩ ⟨_⟩ rfl
     rfl
 
-instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩, ⟨Iso.refl _⟩⟩
+instance : (decomposedTo J).EssSurj where mem_essImage j := ⟨⟨_, j, rfl⟩, ⟨Iso.refl _⟩⟩
 
-instance : IsEquivalence (decomposedTo J) :=
-  Equivalence.ofFullyFaithfullyEssSurj _
+instance : (decomposedTo J).IsEquivalence :=
+  Functor.IsEquivalence.ofFullyFaithfullyEssSurj _
 
 -- Porting note: it was originally @[simps (config := { rhsMd := semireducible }) Functor]
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/

70fd9563

chore(*): remove empty lines between variable statements (#11418)

Empty lines were removed by executing the following Python script twice

import os
import re


# Loop through each file in the repository
for dir_path, dirs, files in os.walk('.'):
  for filename in files:
    if filename.endswith('.lean'):
      file_path = os.path.join(dir_path, filename)

      # Open the file and read its contents
      with open(file_path, 'r') as file:
        content = file.read()

      # Use a regular expression to replace sequences of "variable" lines separated by empty lines
      # with sequences without empty lines
      modified_content = re.sub(r'(variable.*\n)\n(variable(?! .* in))', r'\1\2', content)

      # Write the modified content back to the file
      with open(file_path, 'w') as file:
        file.write(modified_content)

75c86f04

Diff

@@ -33,7 +33,6 @@ namespace CategoryTheory
 attribute [instance 100] IsConnected.is_nonempty
 
 variable {J : Type u₁} [Category.{v₁} J]
-
 variable {C : Type u₂} [Category.{u₁} C]
 
 /-- This type indexes the connected components of the category `J`. -/

70fd9563

chore: remove more autoImplicit (#11336)

... or reduce its scope (the full removal is not as obvious).

59f72a90

Diff

@@ -22,9 +22,6 @@ particular `Decomposed J` is the category (definitionally) given by the sigma-ty
 components of `J`, and it is shown that this is equivalent to `J`.
 -/
 
-set_option autoImplicit true
-
-
 universe v₁ v₂ v₃ u₁ u₂
 
 noncomputable section
@@ -52,6 +49,7 @@ def Component (j : ConnectedComponents J) : Type u₁ :=
   FullSubcategory fun k => Quotient.mk'' k = j
 #align category_theory.component CategoryTheory.Component
 
+set_option autoImplicit true in
 instance : Category (Component (j : ConnectedComponents J)) :=
   FullSubcategory.category _
 
@@ -62,9 +60,11 @@ def Component.ι (j : ConnectedComponents J) : Component j ⥤ J :=
   fullSubcategoryInclusion _
 #align category_theory.component.ι CategoryTheory.Component.ι
 
+set_option autoImplicit true in
 instance : Full (Component.ι (j : ConnectedComponents J)) :=
   FullSubcategory.full _
 
+set_option autoImplicit true in
 instance : Faithful (Component.ι (j : ConnectedComponents J)) :=
   FullSubcategory.faithful _

70fd9563

style: homogenise porting notes (#11145)

Homogenises porting notes via capitalisation and addition of whitespace.

It makes the following changes:

converts "--porting note" into "-- Porting note";
converts "porting note" into "Porting note".

8be0b69c

Diff

@@ -55,7 +55,7 @@ def Component (j : ConnectedComponents J) : Type u₁ :=
 instance : Category (Component (j : ConnectedComponents J)) :=
   FullSubcategory.category _
 
---Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
+-- Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
 /-- The inclusion functor from a connected component to the whole category. -/
 @[simps!]
 def Component.ι (j : ConnectedComponents J) : Component j ⥤ J :=
@@ -118,7 +118,7 @@ abbrev inclusion (j : ConnectedComponents J) : Component j ⥤ Decomposed J :=
   Sigma.incl _
 #align category_theory.inclusion CategoryTheory.inclusion
 
---Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
+-- Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
 /-- The forward direction of the equivalence between the decomposed category and the original. -/
 @[simps!]
 def decomposedTo (J : Type u₁) [Category.{v₁} J] : Decomposed J ⥤ J :=
@@ -159,7 +159,7 @@ instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩,
 instance : IsEquivalence (decomposedTo J) :=
   Equivalence.ofFullyFaithfullyEssSurj _
 
--- porting note: it was originally @[simps (config := { rhsMd := semireducible }) Functor]
+-- Porting note: it was originally @[simps (config := { rhsMd := semireducible }) Functor]
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/
 @[simps! functor]
 def decomposedEquiv : Decomposed J ≌ J :=

70fd9563

style: reduce spacing variation in "porting note" comments (#10886)

In this pull request, I have systematically eliminated the leading whitespace preceding the colon (:) within all unlabelled or unclassified porting notes. This adjustment facilitates a more efficient review process for the remaining notes by ensuring no entries are overlooked due to formatting inconsistencies.

86b84c52

Diff

@@ -55,7 +55,7 @@ def Component (j : ConnectedComponents J) : Type u₁ :=
 instance : Category (Component (j : ConnectedComponents J)) :=
   FullSubcategory.category _
 
---porting note : it was originally @[simps (config := { rhsMd := semireducible })]
+--Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
 /-- The inclusion functor from a connected component to the whole category. -/
 @[simps!]
 def Component.ι (j : ConnectedComponents J) : Component j ⥤ J :=
@@ -118,7 +118,7 @@ abbrev inclusion (j : ConnectedComponents J) : Component j ⥤ Decomposed J :=
   Sigma.incl _
 #align category_theory.inclusion CategoryTheory.inclusion
 
---porting note : it was originally @[simps (config := { rhsMd := semireducible })]
+--Porting note: it was originally @[simps (config := { rhsMd := semireducible })]
 /-- The forward direction of the equivalence between the decomposed category and the original. -/
 @[simps!]
 def decomposedTo (J : Type u₁) [Category.{v₁} J] : Decomposed J ⥤ J :=

70fd9563

chore: avoid lean3 style have/suffices (#6964)

Many proofs use the "stream of consciousness" style from Lean 3, rather than have ... := or suffices ... from/by.

This PR updates a fraction of these to the preferred Lean 4 style.

I think a good goal would be to delete the "deferred" versions of have, suffices, and let at the bottom of Mathlib.Tactic.Have

(Anyone who would like to contribute more cleanup is welcome to push directly to this branch.)

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

bdc47f68

Diff

@@ -136,9 +136,9 @@ instance : Full (decomposedTo J)
   preimage := by
     rintro ⟨j', X, hX⟩ ⟨k', Y, hY⟩ f
     dsimp at f
-    have : j' = k'
-    rw [← hX, ← hY, Quotient.eq'']
-    exact Relation.ReflTransGen.single (Or.inl ⟨f⟩)
+    have : j' = k' := by
+      rw [← hX, ← hY, Quotient.eq'']
+      exact Relation.ReflTransGen.single (Or.inl ⟨f⟩)
     subst this
     exact Sigma.SigmaHom.mk f
   witness := by

70fd9563

fix: disable autoImplicit globally (#6528)

Autoimplicits are highly controversial and also defeat the performance-improving work in #6474.

The intent of this PR is to make autoImplicit opt-in on a per-file basis, by disabling it in the lakefile and enabling it again with set_option autoImplicit true in the few files that rely on it.

That also keeps this PR small, as opposed to attempting to "fix" files to not need it any more.

I claim that many of the uses of autoImplicit in these files are accidental; situations such as:

Assuming variables are in scope, but pasting the lemma in the wrong section
Pasting in a lemma from a scratch file without checking to see if the variable names are consistent with the rest of the file
Making a copy-paste error between lemmas and forgetting to add an explicit arguments.

Having set_option autoImplicit false as the default prevents these types of mistake being made in the 90% of files where autoImplicits are not used at all, and causes them to be caught by CI during review.

I think there were various points during the port where we encouraged porters to delete the universes u v lines; I think having autoparams for universe variables only would cover a lot of the cases we actually use them, while avoiding any real shortcomings.

A Zulip poll (after combining overlapping votes accordingly) was in favor of this change with 5:5:18 as the no:dontcare:yes vote ratio.

While this PR was being reviewed, a handful of files gained some more likely-accidental autoImplicits. In these places, set_option autoImplicit true has been placed locally within a section, rather than at the top of the file.

0c24f831

Diff

@@ -22,6 +22,8 @@ particular `Decomposed J` is the category (definitionally) given by the sigma-ty
 components of `J`, and it is shown that this is equivalent to `J`.
 -/
 
+set_option autoImplicit true
+
 
 universe v₁ v₂ v₃ u₁ u₂

70fd9563

chore: script to replace headers with #align_import statements (#5979)

depends on: #5966

Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

89aa3a3b

Diff

@@ -2,17 +2,14 @@
 Copyright (c) 2020 Bhavik Mehta. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Bhavik Mehta
-
-! This file was ported from Lean 3 source module category_theory.connected_components
-! leanprover-community/mathlib commit 70fd9563a21e7b963887c9360bd29b2393e6225a
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Data.List.Chain
 import Mathlib.CategoryTheory.IsConnected
 import Mathlib.CategoryTheory.Sigma.Basic
 import Mathlib.CategoryTheory.FullSubcategory
 
+#align_import category_theory.connected_components from "leanprover-community/mathlib"@"70fd9563a21e7b963887c9360bd29b2393e6225a"
+
 /-!
 # Connected components of a category

70fd9563

chore: fix many typos (#4967)

These are all doc fixes

6f9e51c3

Diff

@@ -160,7 +160,7 @@ instance : EssSurj (decomposedTo J) where mem_essImage j := ⟨⟨_, j, rfl⟩,
 instance : IsEquivalence (decomposedTo J) :=
   Equivalence.ofFullyFaithfullyEssSurj _
 
--- portint note: it was originally @[simps (config := { rhsMd := semireducible }) Functor]
+-- porting note: it was originally @[simps (config := { rhsMd := semireducible }) Functor]
 /-- This gives that any category is equivalent to a disjoint union of connected categories. -/
 @[simps! functor]
 def decomposedEquiv : Decomposed J ≌ J :=

70fd9563

chore: port missing instance priorities (#3613)

See discussion at https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/mathport.20drops.20priorities.20in.20.60attribute.20.5Binstance.5D.60. mathport has been dropping the priorities on instances when using the attribute command.

This PR adds back all the priorities, except for local attribute, and instances involving coercions, which I didn't want to mess with.

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

b0c1460c

Diff

@@ -34,7 +34,7 @@ open CategoryTheory.Category
 
 namespace CategoryTheory
 
-attribute [instance] IsConnected.is_nonempty
+attribute [instance 100] IsConnected.is_nonempty
 
 variable {J : Type u₁} [Category.{v₁} J]

70fd9563

fix: remove unneeded LibrarySearch imports (#3353)

Removes LibrarySearch imports that were accidentally included in #2843 and #2361.

3fb0331e

Diff

@@ -12,7 +12,6 @@ import Mathlib.Data.List.Chain
 import Mathlib.CategoryTheory.IsConnected
 import Mathlib.CategoryTheory.Sigma.Basic
 import Mathlib.CategoryTheory.FullSubcategory
-import Mathlib.Tactic.LibrarySearch
 
 /-!
 # Connected components of a category

70fd9563

feat: port CategoryTheory.ConnectedComponents (#2843)

b3e1613e

`category_theory.connected_components` ⟷ `Mathlib.CategoryTheory.ConnectedComponents`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 2 + 122

category_theory.connected_components ⟷ Mathlib.CategoryTheory.ConnectedComponents

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 2 + 122

`category_theory.connected_components` ⟷ `Mathlib.CategoryTheory.ConnectedComponents`