category_theory.pempty | 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

2738d2ca

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

23aa88e3

bump to nightly-2023-10-28-06

mathlib commit https://github.com/leanprover-community/mathlib/commit/3365b20c2ffa7c35e47e5209b89ba9abdddf3ffe

d83d09a1

Diff

@@ -26,15 +26,15 @@ namespace Functor
 
 variable (C : Type u) [Category.{v} C]
 
-#print CategoryTheory.Functor.emptyEquivalence /-
+#print CategoryTheory.emptyEquivalence /-
 /-- Equivalence between two empty categories. -/
-def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
+def CategoryTheory.emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
   Equivalence.mk
     { obj := PEmpty.elim ∘ Discrete.as
       map := fun x => x.as.elim }
     { obj := PEmpty.elim ∘ Discrete.as
       map := fun x => x.as.elim } (by tidy) (by tidy)
-#align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalence
+#align category_theory.functor.empty_equivalence CategoryTheory.emptyEquivalence
 -/
 
 #print CategoryTheory.Functor.empty /-

23aa88e3

bump to nightly-2023-09-24-06

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

5655435f

Diff

@@ -3,7 +3,7 @@ Copyright (c) 2018 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison, Bhavik Mehta
 -/
-import Mathbin.CategoryTheory.DiscreteCategory
+import CategoryTheory.DiscreteCategory
 
 #align_import category_theory.pempty from "leanprover-community/mathlib"@"23aa88e32dcc9d2a24cca7bc23268567ed4cd7d6"

23aa88e3

bump to nightly-2023-07-20-09

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

9c56d0dd

Diff

@@ -2,14 +2,11 @@
 Copyright (c) 2018 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison, Bhavik Mehta
-
-! This file was ported from Lean 3 source module category_theory.pempty
-! leanprover-community/mathlib commit 23aa88e32dcc9d2a24cca7bc23268567ed4cd7d6
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.CategoryTheory.DiscreteCategory
 
+#align_import category_theory.pempty from "leanprover-community/mathlib"@"23aa88e32dcc9d2a24cca7bc23268567ed4cd7d6"
+
 /-!
 # The empty category

23aa88e3

bump to nightly-2023-06-13-21

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

829520ac

Diff

@@ -29,6 +29,7 @@ namespace Functor
 
 variable (C : Type u) [Category.{v} C]
 
+#print CategoryTheory.Functor.emptyEquivalence /-
 /-- Equivalence between two empty categories. -/
 def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
   Equivalence.mk
@@ -37,6 +38,7 @@ def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
     { obj := PEmpty.elim ∘ Discrete.as
       map := fun x => x.as.elim } (by tidy) (by tidy)
 #align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalence
+-/
 
 #print CategoryTheory.Functor.empty /-
 /-- The canonical functor out of the empty category. -/

23aa88e3

bump to nightly-2023-05-28-06

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

ba5d8b97

Diff

@@ -29,12 +29,6 @@ namespace Functor
 
 variable (C : Type u) [Category.{v} C]
 
-/- warning: category_theory.functor.empty_equivalence -> CategoryTheory.Functor.emptyEquivalence is a dubious translation:
-lean 3 declaration is
-  CategoryTheory.Equivalence.{u1, u2, u1, u2} (CategoryTheory.Discrete.{u1} PEmpty.{succ u1}) (CategoryTheory.discreteCategory.{u1} PEmpty.{succ u1}) (CategoryTheory.Discrete.{u2} PEmpty.{succ u2}) (CategoryTheory.discreteCategory.{u2} PEmpty.{succ u2})
-but is expected to have type
-  CategoryTheory.Equivalence.{u1, u2, u1, u2} (CategoryTheory.Discrete.{u1} PEmpty.{succ u1}) (CategoryTheory.Discrete.{u2} PEmpty.{succ u2}) (CategoryTheory.discreteCategory.{u1} PEmpty.{succ u1}) (CategoryTheory.discreteCategory.{u2} PEmpty.{succ u2})
-Case conversion may be inaccurate. Consider using '#align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalenceₓ'. -/
 /-- Equivalence between two empty categories. -/
 def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
   Equivalence.mk

23aa88e3

bump to nightly-2023-02-23-03

mathlib commit https://github.com/leanprover-community/mathlib/commit/3ade05ac9447ae31a22d2ea5423435e054131240

5c91f1b0

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison, Bhavik Mehta
 
 ! This file was ported from Lean 3 source module category_theory.pempty
-! leanprover-community/mathlib commit c9c9fa15fec7ca18e9ec97306fb8764bfe988a7e
+! leanprover-community/mathlib commit 23aa88e32dcc9d2a24cca7bc23268567ed4cd7d6
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -13,6 +13,9 @@ import Mathbin.CategoryTheory.DiscreteCategory
 /-!
 # The empty category
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 Defines a category structure on `pempty`, and the unique functor `pempty ⥤ C` for any category `C`.
 -/

c9c9fa15

bump to nightly-2023-02-21-22

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

d36dd541

Diff

@@ -26,6 +26,12 @@ namespace Functor
 
 variable (C : Type u) [Category.{v} C]
 
+/- warning: category_theory.functor.empty_equivalence -> CategoryTheory.Functor.emptyEquivalence is a dubious translation:
+lean 3 declaration is
+  CategoryTheory.Equivalence.{u1, u2, u1, u2} (CategoryTheory.Discrete.{u1} PEmpty.{succ u1}) (CategoryTheory.discreteCategory.{u1} PEmpty.{succ u1}) (CategoryTheory.Discrete.{u2} PEmpty.{succ u2}) (CategoryTheory.discreteCategory.{u2} PEmpty.{succ u2})
+but is expected to have type
+  CategoryTheory.Equivalence.{u1, u2, u1, u2} (CategoryTheory.Discrete.{u1} PEmpty.{succ u1}) (CategoryTheory.Discrete.{u2} PEmpty.{succ u2}) (CategoryTheory.discreteCategory.{u1} PEmpty.{succ u1}) (CategoryTheory.discreteCategory.{u2} PEmpty.{succ u2})
+Case conversion may be inaccurate. Consider using '#align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalenceₓ'. -/
 /-- Equivalence between two empty categories. -/
 def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
   Equivalence.mk
@@ -35,31 +41,39 @@ def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty :=
       map := fun x => x.as.elim } (by tidy) (by tidy)
 #align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalence
 
+#print CategoryTheory.Functor.empty /-
 /-- The canonical functor out of the empty category. -/
 def empty : Discrete.{w} PEmpty ⥤ C :=
   Discrete.functor PEmpty.elim
 #align category_theory.functor.empty CategoryTheory.Functor.empty
+-/
 
 variable {C}
 
+#print CategoryTheory.Functor.emptyExt /-
 /-- Any two functors out of the empty category are isomorphic. -/
 def emptyExt (F G : Discrete.{w} PEmpty ⥤ C) : F ≅ G :=
   Discrete.natIso fun x => x.as.elim
 #align category_theory.functor.empty_ext CategoryTheory.Functor.emptyExt
+-/
 
+#print CategoryTheory.Functor.uniqueFromEmpty /-
 /-- Any functor out of the empty category is isomorphic to the canonical functor from the empty
 category.
 -/
 def uniqueFromEmpty (F : Discrete.{w} PEmpty ⥤ C) : F ≅ empty C :=
   emptyExt _ _
 #align category_theory.functor.unique_from_empty CategoryTheory.Functor.uniqueFromEmpty
+-/
 
+#print CategoryTheory.Functor.empty_ext' /-
 /-- Any two functors out of the empty category are *equal*. You probably want to use
 `empty_ext` instead of this.
 -/
 theorem empty_ext' (F G : Discrete.{w} PEmpty ⥤ C) : F = G :=
   Functor.ext (fun x => x.as.elim) fun x _ _ => x.as.elim
 #align category_theory.functor.empty_ext' CategoryTheory.Functor.empty_ext'
+-/
 
 end Functor

c9c9fa15

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

2738d2ca

feat(CategoryTheory/Limits/VanKampen): Properties of van Kampen colimits (#7745)

Also moves the definition of van Kampen colimits from CategoryTheory/Extensive.lean into a new file.

Co-authored-by: Andrew Yang <36414270+erdOne@users.noreply.github.com> Co-authored-by: Mario Carneiro <di.gama@gmail.com>

3716d38c

Diff

@@ -13,29 +13,42 @@ import Mathlib.CategoryTheory.DiscreteCategory
 Defines a category structure on `PEmpty`, and the unique functor `PEmpty ⥤ C` for any category `C`.
 -/
 
-universe w v u
+universe w v v' u u'
 -- morphism levels before object levels. See note [CategoryTheory universes].
 namespace CategoryTheory
 
-namespace Functor
+variable (C : Type u) [Category.{v} C] (D : Type u') [Category.{v'} D]
+
+instance (α : Type*) [IsEmpty α] : IsEmpty (Discrete α) := Function.isEmpty Discrete.as
+
+/-- The (unique) functor from an empty category. -/
+def functorOfIsEmpty [IsEmpty C] : C ⥤ D where
+  obj := isEmptyElim
+  map := fun {X} ↦ isEmptyElim X
+  map_id := fun {X} ↦ isEmptyElim X
+  map_comp := fun {X} ↦ isEmptyElim X
+
+variable {C D}
 
-variable (C : Type u) [Category.{v} C]
+/-- Any two functors out of an empty category are isomorphic. -/
+def Functor.isEmptyExt [IsEmpty C] (F G : C ⥤ D) : F ≅ G :=
+  NatIso.ofComponents isEmptyElim (fun {X} ↦ isEmptyElim X)
+
+variable (C D)
+
+/-- The equivalence between two empty categories. -/
+def equivalenceOfIsEmpty [IsEmpty C] [IsEmpty D] : C ≌ D where
+  functor := functorOfIsEmpty C D
+  inverse := functorOfIsEmpty D C
+  unitIso := Functor.isEmptyExt _ _
+  counitIso := Functor.isEmptyExt _ _
+  functor_unitIso_comp := isEmptyElim
 
 /-- Equivalence between two empty categories. -/
-def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty where
-  functor :=
-    { obj := PEmpty.elim ∘ Discrete.as
-      map := fun {X} _ _ => X.as.elim }
-  inverse :=
-    { obj := PEmpty.elim ∘ Discrete.as
-      map := fun {X} _ _ => X.as.elim }
-  unitIso :=
-    { hom := { app := fun X => X.as.elim }
-      inv := { app := fun X => X.as.elim } }
-  counitIso :=
-    { hom := { app := fun X => X.as.elim }
-      inv := { app := fun X => X.as.elim } }
-#align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalence
+def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty := equivalenceOfIsEmpty _ _
+#align category_theory.functor.empty_equivalence CategoryTheory.emptyEquivalence
+
+namespace Functor
 
 /-- The canonical functor out of the empty category. -/
 def empty : Discrete.{w} PEmpty ⥤ C :=

2738d2ca

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

@@ -2,14 +2,11 @@
 Copyright (c) 2018 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison, Bhavik Mehta
-
-! This file was ported from Lean 3 source module category_theory.pempty
-! leanprover-community/mathlib commit 2738d2ca56cbc63be80c3bd48e9ed90ad94e947d
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.CategoryTheory.DiscreteCategory
 
+#align_import category_theory.pempty from "leanprover-community/mathlib"@"2738d2ca56cbc63be80c3bd48e9ed90ad94e947d"
+
 /-!
 # The empty category

2738d2ca

feat: add Aesop rules for Discrete category (#2519)

Adds a global Aesop cases rule for the Discrete category. This rule was previously added locally in several places.

ecb36a8f

Diff

@@ -16,8 +16,6 @@ import Mathlib.CategoryTheory.DiscreteCategory
 Defines a category structure on `PEmpty`, and the unique functor `PEmpty ⥤ C` for any category `C`.
 -/
 
--- Porting note: this file stressed Lean a good deal despite its length
-
 universe w v u
 -- morphism levels before object levels. See note [CategoryTheory universes].
 namespace CategoryTheory

2738d2ca

chore: review of automation in category theory (#4793)

Clean up of automation in the category theory library. Leaving out unnecessary proof steps, or fields done by aesop_cat, and making more use of available autoparameters.

Co-authored-by: Scott Morrison <scott.morrison@anu.edu.au>

5b958613

Diff

@@ -25,33 +25,21 @@ namespace CategoryTheory
 namespace Functor
 
 variable (C : Type u) [Category.{v} C]
-/- Porting note: `aesop_cat` could not close any of the goals `tidy` did.
-Switched to more explicit construction -/
+
 /-- Equivalence between two empty categories. -/
 def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty where
   functor :=
     { obj := PEmpty.elim ∘ Discrete.as
-      map := fun {X} _ _ => X.as.elim
-      map_comp := fun {X} _ _ _ _ => X.as.elim }
+      map := fun {X} _ _ => X.as.elim }
   inverse :=
     { obj := PEmpty.elim ∘ Discrete.as
-      map := fun {X} _ _ => X.as.elim
-      map_comp := fun {X} _ _ _ _ => X.as.elim }
+      map := fun {X} _ _ => X.as.elim }
   unitIso :=
-    { hom :=
-        { app := fun X => X.as.elim
-          naturality := fun {X} _ _ => X.as.elim }
-      inv :=
-        { app := fun X => X.as.elim
-          naturality := fun {X} _ _ => X.as.elim } }
+    { hom := { app := fun X => X.as.elim }
+      inv := { app := fun X => X.as.elim } }
   counitIso :=
-    { hom :=
-        { app := fun X => X.as.elim
-          naturality := fun {X} _ _ => X.as.elim }
-      inv :=
-        { app := fun X => X.as.elim
-          naturality := fun {X} _ _ => X.as.elim } }
-  functor_unitIso_comp := fun X => X.as.elim
+    { hom := { app := fun X => X.as.elim }
+      inv := { app := fun X => X.as.elim } }
 #align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalence
 
 /-- The canonical functor out of the empty category. -/

2738d2ca

chore: fix typos (#4518)

I ran codespell Mathlib and got tired halfway through the suggestions.

92beef58

Diff

@@ -26,7 +26,7 @@ namespace Functor
 
 variable (C : Type u) [Category.{v} C]
 /- Porting note: `aesop_cat` could not close any of the goals `tidy` did.
-Switched to more explict construction -/
+Switched to more explicit construction -/
 /-- Equivalence between two empty categories. -/
 def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty where
   functor :=

2738d2ca

chore: strip trailing spaces in lean files (#2828)

vscode is already configured by .vscode/settings.json to trim these on save. It's not clear how they've managed to stick around.

By doing this all in one PR now, it avoids getting random whitespace diffs in PRs later.

This was done with a regex search in vscode,

6ceb5945

Diff

@@ -25,33 +25,33 @@ namespace CategoryTheory
 namespace Functor
 
 variable (C : Type u) [Category.{v} C]
-/- Porting note: `aesop_cat` could not close any of the goals `tidy` did. 
+/- Porting note: `aesop_cat` could not close any of the goals `tidy` did.
 Switched to more explict construction -/
 /-- Equivalence between two empty categories. -/
-def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty where 
-  functor := 
+def emptyEquivalence : Discrete.{w} PEmpty ≌ Discrete.{v} PEmpty where
+  functor :=
     { obj := PEmpty.elim ∘ Discrete.as
-      map := fun {X} _ _ => X.as.elim 
+      map := fun {X} _ _ => X.as.elim
       map_comp := fun {X} _ _ _ _ => X.as.elim }
-  inverse := 
+  inverse :=
     { obj := PEmpty.elim ∘ Discrete.as
-      map := fun {X} _ _ => X.as.elim  
+      map := fun {X} _ _ => X.as.elim
       map_comp := fun {X} _ _ _ _ => X.as.elim }
-  unitIso := 
-    { hom := 
-        { app := fun X => X.as.elim 
+  unitIso :=
+    { hom :=
+        { app := fun X => X.as.elim
           naturality := fun {X} _ _ => X.as.elim }
-      inv := 
-        { app := fun X => X.as.elim 
+      inv :=
+        { app := fun X => X.as.elim
           naturality := fun {X} _ _ => X.as.elim } }
-  counitIso := 
-    { hom := 
-        { app := fun X => X.as.elim 
+  counitIso :=
+    { hom :=
+        { app := fun X => X.as.elim
           naturality := fun {X} _ _ => X.as.elim }
-      inv := 
-        { app := fun X => X.as.elim 
+      inv :=
+        { app := fun X => X.as.elim
           naturality := fun {X} _ _ => X.as.elim } }
-  functor_unitIso_comp := fun X => X.as.elim  
+  functor_unitIso_comp := fun X => X.as.elim
 #align category_theory.functor.empty_equivalence CategoryTheory.Functor.emptyEquivalence
 
 /-- The canonical functor out of the empty category. -/
@@ -83,4 +83,3 @@ theorem empty_ext' (F G : Discrete.{w} PEmpty ⥤ C) : F = G :=
 end Functor
 
 end CategoryTheory
-

2738d2ca

feat: port/CategoryTheory.PEmpty (#2363)

Co-authored-by: Matthew Ballard <matt@mrb.email> Co-authored-by: Matthew Robert Ballard <100034030+mattrobball@users.noreply.github.com>

f327ca89

`category_theory.pempty` ⟷ `Mathlib.CategoryTheory.PEmpty`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 31

category_theory.pempty ⟷ Mathlib.CategoryTheory.PEmpty

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 31

`category_theory.pempty` ⟷ `Mathlib.CategoryTheory.PEmpty`