data.countable.defs | 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

70d50ecf

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

448144f7

bump to nightly-2024-02-05-08

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

516c6ec2

Diff

@@ -33,7 +33,7 @@ variable {α : Sort u} {β : Sort v}
 
 
 #print Countable /-
-/- ./././Mathport/Syntax/Translate/Command.lean:404:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
+/- ./././Mathport/Syntax/Translate/Command.lean:400:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where

448144f7

bump to nightly-2023-12-23-06

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

b8c74971

Diff

@@ -33,7 +33,7 @@ variable {α : Sort u} {β : Sort v}
 
 
 #print Countable /-
-/- ./././Mathport/Syntax/Translate/Command.lean:394:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
+/- ./././Mathport/Syntax/Translate/Command.lean:404:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where

448144f7

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) 2022 Yury Kudryashov. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
 -/
-import Mathbin.Data.Finite.Defs
+import Data.Finite.Defs
 
 #align_import data.countable.defs from "leanprover-community/mathlib"@"448144f7ae193a8990cb7473c9e9a01990f64ac7"
 
@@ -33,7 +33,7 @@ variable {α : Sort u} {β : Sort v}
 
 
 #print Countable /-
-/- ./././Mathport/Syntax/Translate/Command.lean:393:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
+/- ./././Mathport/Syntax/Translate/Command.lean:394:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where

448144f7

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) 2022 Yury Kudryashov. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
-
-! This file was ported from Lean 3 source module data.countable.defs
-! leanprover-community/mathlib commit 448144f7ae193a8990cb7473c9e9a01990f64ac7
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Data.Finite.Defs
 
+#align_import data.countable.defs from "leanprover-community/mathlib"@"448144f7ae193a8990cb7473c9e9a01990f64ac7"
+
 /-!
 # Countable types

448144f7

bump to nightly-2023-06-13-21

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

829520ac

Diff

@@ -36,7 +36,7 @@ variable {α : Sort u} {β : Sort v}
 
 
 #print Countable /-
-/- ./././Mathport/Syntax/Translate/Command.lean:394:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
+/- ./././Mathport/Syntax/Translate/Command.lean:393:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where
@@ -77,9 +77,11 @@ theorem countable_iff_exists_surjective [Nonempty α] : Countable α ↔ ∃ f :
 #align countable_iff_exists_surjective countable_iff_exists_surjective
 -/
 
+#print Countable.of_equiv /-
 theorem Countable.of_equiv (α : Sort _) [Countable α] (e : α ≃ β) : Countable β :=
   e.symm.Injective.Countable
 #align countable.of_equiv Countable.of_equiv
+-/
 
 #print Equiv.countable_iff /-
 theorem Equiv.countable_iff (e : α ≃ β) : Countable α ↔ Countable β :=

448144f7

bump to nightly-2023-06-04-18

mathlib commit https://github.com/leanprover-community/mathlib/commit/5f25c089cb34db4db112556f23c50d12da81b297

3fb4268b

Diff

@@ -36,7 +36,7 @@ variable {α : Sort u} {β : Sort v}
 
 
 #print Countable /-
-/- ./././Mathport/Syntax/Translate/Command.lean:393:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
+/- ./././Mathport/Syntax/Translate/Command.lean:394:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where

448144f7

bump to nightly-2023-05-28-06

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

ba5d8b97

Diff

@@ -77,12 +77,6 @@ theorem countable_iff_exists_surjective [Nonempty α] : Countable α ↔ ∃ f :
 #align countable_iff_exists_surjective countable_iff_exists_surjective
 -/
 
-/- warning: countable.of_equiv -> Countable.of_equiv is a dubious translation:
-lean 3 declaration is
-  forall {β : Sort.{u1}} (α : Sort.{u2}) [_inst_1 : Countable.{u2} α], (Equiv.{u2, u1} α β) -> (Countable.{u1} β)
-but is expected to have type
-  forall {β : Sort.{u2}} (α : Sort.{u1}) [_inst_1 : Countable.{u1} α], (Equiv.{u1, u2} α β) -> (Countable.{u2} β)
-Case conversion may be inaccurate. Consider using '#align countable.of_equiv Countable.of_equivₓ'. -/
 theorem Countable.of_equiv (α : Sort _) [Countable α] (e : α ≃ β) : Countable β :=
   e.symm.Injective.Countable
 #align countable.of_equiv Countable.of_equiv

448144f7

bump to nightly-2023-04-24-06

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

ff662d55

Diff

@@ -36,7 +36,7 @@ variable {α : Sort u} {β : Sort v}
 
 
 #print Countable /-
-/- ./././Mathport/Syntax/Translate/Command.lean:388:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
+/- ./././Mathport/Syntax/Translate/Command.lean:393:30: infer kinds are unsupported in Lean 4: #[`exists_injective_nat] [] -/
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where

448144f7

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

70d50ecf

chore(Init/Fin): deprecate Fin.eq_of_veq and Fin.veq_of_eq (#10626)

We have Fin.eq_of_val_eq and Fin.val_eq_of_eq in Lean core now. Also slightly shake the tree.

9a944835

Diff

@@ -5,8 +5,8 @@ Authors: Yury Kudryashov
 -/
 import Mathlib.Data.Finite.Defs
 import Mathlib.Data.Bool.Basic
-import Mathlib.Init.Data.Fin.Basic
-import Mathlib.Tactic.Common
+import Mathlib.Data.Subtype
+import Mathlib.Tactic.MkIffOfInductiveProp
 
 #align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"
 
@@ -96,7 +96,7 @@ instance (priority := 500) Subtype.countable [Countable α] {p : α → Prop} :
   Subtype.val_injective.countable
 
 instance {n : ℕ} : Countable (Fin n) :=
-  Function.Injective.countable (@Fin.eq_of_veq n)
+  Function.Injective.countable (@Fin.eq_of_val_eq n)
 
 instance (priority := 100) Finite.to_countable [Finite α] : Countable α :=
   let ⟨_, ⟨e⟩⟩ := Finite.exists_equiv_fin α

70d50ecf

chore: reduce imports (#9830)

This uses the improved shake script from #9772 to reduce imports across mathlib. The corresponding noshake.json file has been added to #9772.

Co-authored-by: Mario Carneiro <di.gama@gmail.com>

f4c4ca61

Diff

@@ -4,8 +4,8 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
 -/
 import Mathlib.Data.Finite.Defs
+import Mathlib.Data.Bool.Basic
 import Mathlib.Init.Data.Fin.Basic
-import Mathlib.Logic.Equiv.Basic
 import Mathlib.Tactic.Common
 
 #align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"

70d50ecf

chore: Move Int and Nat cast lemmas (#9503)

Part of #9411

e1b05c51

Diff

@@ -5,6 +5,7 @@ Authors: Yury Kudryashov
 -/
 import Mathlib.Data.Finite.Defs
 import Mathlib.Init.Data.Fin.Basic
+import Mathlib.Logic.Equiv.Basic
 import Mathlib.Tactic.Common
 
 #align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"

70d50ecf

feat: Add Uncountable (#9254)

Adds the Uncountable class to Countable/Defs and some basic API.

Co-authored-by: Yury G. Kudryashov <urkud@urkud.name>

b50557ce

Diff

@@ -10,15 +10,17 @@ import Mathlib.Tactic.Common
 #align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"
 
 /-!
-# Countable types
+# Countable and uncountable types
 
-In this file we define a typeclass saying that a given `Sort*` is countable. See also `Encodable`
-for a version that singles out a specific encoding of elements of `α` by natural numbers.
+In this file we define a typeclass `Countable` saying that a given `Sort*` is countable
+and a typeclass `Uncountable` saying that a given `Type*` is uncountable.
 
-This file also provides a few instances of this typeclass. More instances can be found in other
-files.
--/
+See also `Encodable` for a version that singles out
+a specific encoding of elements of `α` by natural numbers.
 
+This file also provides a few instances of these typeclasses.
+More instances can be found in other files.
+-/
 
 open Function
 
@@ -117,3 +119,57 @@ instance (priority := 500) Quotient.countable [Countable α] {r : α → α →
 
 instance (priority := 500) [Countable α] {s : Setoid α} : Countable (Quotient s) :=
   (inferInstance : Countable (@Quot α _))
+
+/-!
+### Uncountable types
+-/
+
+/-- A type `α` is uncountable if it is not countable. -/
+@[mk_iff uncountable_iff_not_countable]
+class Uncountable (α : Sort*) : Prop where
+  /-- A type `α` is uncountable if it is not countable. -/
+  not_countable : ¬Countable α
+
+lemma not_uncountable_iff : ¬Uncountable α ↔ Countable α := by
+  rw [uncountable_iff_not_countable, not_not]
+
+lemma not_countable_iff : ¬Countable α ↔ Uncountable α := (uncountable_iff_not_countable α).symm
+
+@[simp]
+lemma not_uncountable [Countable α] : ¬Uncountable α := not_uncountable_iff.2 ‹_›
+
+@[simp]
+lemma not_countable [Uncountable α] : ¬Countable α := Uncountable.not_countable
+
+protected theorem Function.Injective.uncountable [Uncountable α] {f : α → β} (hf : Injective f) :
+    Uncountable β :=
+  ⟨fun _ ↦ not_countable hf.countable⟩
+
+protected theorem Function.Surjective.uncountable [Uncountable β] {f : α → β} (hf : Surjective f) :
+    Uncountable α := (injective_surjInv hf).uncountable
+
+lemma not_injective_uncountable_countable [Uncountable α] [Countable β] (f : α → β) :
+    ¬Injective f := fun hf ↦ not_countable hf.countable
+
+lemma not_surjective_countable_uncountable [Countable α] [Uncountable β] (f : α → β) :
+    ¬Surjective f := fun hf ↦
+  not_countable hf.countable
+
+theorem uncountable_iff_forall_not_surjective [Nonempty α] :
+    Uncountable α ↔ ∀ f : ℕ → α, ¬Surjective f := by
+  rw [← not_countable_iff, countable_iff_exists_surjective, not_exists]
+
+theorem Uncountable.of_equiv (α : Sort*) [Uncountable α] (e : α ≃ β) : Uncountable β :=
+  e.injective.uncountable
+
+theorem Equiv.uncountable_iff (e : α ≃ β) : Uncountable α ↔ Uncountable β :=
+  ⟨fun h => @Uncountable.of_equiv _ _ h e, fun h => @Uncountable.of_equiv _ _ h e.symm⟩
+
+instance {β : Type v} [Uncountable β] : Uncountable (ULift.{u} β) :=
+  .of_equiv _ Equiv.ulift.symm
+
+instance [Uncountable α] : Uncountable (PLift α) :=
+  .of_equiv _ Equiv.plift.symm
+
+instance (priority := 100) [Uncountable α] : Infinite α :=
+  ⟨fun _ ↦ not_countable (α := α) inferInstance⟩

70d50ecf

refactor(Logic/Unique): remove dependency on Fin (#8510)

Unique should be available earlier than results about Fin n, by virtue of being a very basic logic typeclass with no dependencies on Nat or algebra.

This also generalizes some of the moved instances and lemmas. There are no new declarations in this PR, only renames of existing ones.

8b144faa

Diff

@@ -4,6 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
 -/
 import Mathlib.Data.Finite.Defs
+import Mathlib.Init.Data.Fin.Basic
 import Mathlib.Tactic.Common
 
 #align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"

70d50ecf

chore: tidy various files (#7343)

ee7626c6

Diff

@@ -38,7 +38,7 @@ class Countable (α : Sort u) : Prop where
 #align countable_iff_exists_injective countable_iff_exists_injective
 
 lemma Countable.exists_injective_nat (α : Sort u) [Countable α] : ∃ f : α → ℕ, Injective f :=
-Countable.exists_injective_nat'
+  Countable.exists_injective_nat'
 
 instance : Countable ℕ :=
   ⟨⟨id, injective_id⟩⟩

70d50ecf

chore: exactly 4 spaces in subsequent lines (#7296)

Co-authored-by: Moritz Firsching <firsching@google.com>

43ed95ab

Diff

@@ -46,13 +46,13 @@ instance : Countable ℕ :=
 export Countable (exists_injective_nat)
 
 protected theorem Function.Injective.countable [Countable β] {f : α → β} (hf : Injective f) :
-  Countable α :=
+    Countable α :=
   let ⟨g, hg⟩ := exists_injective_nat β
   ⟨⟨g ∘ f, hg.comp hf⟩⟩
 #align function.injective.countable Function.Injective.countable
 
 protected theorem Function.Surjective.countable [Countable α] {f : α → β} (hf : Surjective f) :
-  Countable β :=
+    Countable β :=
   (injective_surjInv hf).countable
 #align function.surjective.countable Function.Surjective.countable

70d50ecf

chore: only four spaces for subsequent lines (#7286)

Co-authored-by: Moritz Firsching <firsching@google.com>

0c7d6fa5

Diff

@@ -37,8 +37,7 @@ class Countable (α : Sort u) : Prop where
 #align countable Countable
 #align countable_iff_exists_injective countable_iff_exists_injective
 
-lemma Countable.exists_injective_nat (α : Sort u) [Countable α] :
-  ∃ f : α → ℕ, Injective f :=
+lemma Countable.exists_injective_nat (α : Sort u) [Countable α] : ∃ f : α → ℕ, Injective f :=
 Countable.exists_injective_nat'
 
 instance : Countable ℕ :=

70d50ecf

chore: delay import of Tactic.Common (#7000)

I know that this is contrary to what we've done previously, but:

I'm trying to upstream a great many tactics from Mathlib to Std (essentially, everything that non-mathematicians want too).
This makes it much easier for me to see what is going on, and understand the import requirements (particularly for the "big" tactics norm_num / ring / linarith)
It's actually not as bad as it looks here, because as these tactics move up to Std they will start disappearing again from explicit imports, but Mathlib can happily import all of Std.

(Oh

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

4f3418a7

Diff

@@ -4,6 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
 -/
 import Mathlib.Data.Finite.Defs
+import Mathlib.Tactic.Common
 
 #align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"

70d50ecf

chore: banish Type _ and Sort _ (#6499)

We remove all possible occurences of Type _ and Sort _ in favor of Type* and Sort*.

This has nice performance benefits.

32de3f67

Diff

@@ -10,7 +10,7 @@ import Mathlib.Data.Finite.Defs
 /-!
 # Countable types
 
-In this file we define a typeclass saying that a given `Sort _` is countable. See also `Encodable`
+In this file we define a typeclass saying that a given `Sort*` is countable. See also `Encodable`
 for a version that singles out a specific encoding of elements of `α` by natural numbers.
 
 This file also provides a few instances of this typeclass. More instances can be found in other
@@ -65,7 +65,7 @@ theorem countable_iff_exists_surjective [Nonempty α] : Countable α ↔ ∃ f :
   ⟨@exists_surjective_nat _ _, fun ⟨_, hf⟩ ↦ hf.countable⟩
 #align countable_iff_exists_surjective countable_iff_exists_surjective
 
-theorem Countable.of_equiv (α : Sort _) [Countable α] (e : α ≃ β) : Countable β :=
+theorem Countable.of_equiv (α : Sort*) [Countable α] (e : α ≃ β) : Countable β :=
   e.symm.injective.countable
 #align countable.of_equiv Countable.of_equiv
 
@@ -77,7 +77,7 @@ instance {β : Type v} [Countable β] : Countable (ULift.{u} β) :=
   Countable.of_equiv _ Equiv.ulift.symm
 
 /-!
-### Operations on `Sort _`s
+### Operations on `Sort*`s
 -/

70d50ecf

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) 2022 Yury Kudryashov. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
-
-! This file was ported from Lean 3 source module data.countable.defs
-! leanprover-community/mathlib commit 70d50ecfd4900dd6d328da39ab7ebd516abe4025
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Data.Finite.Defs
 
+#align_import data.countable.defs from "leanprover-community/mathlib"@"70d50ecfd4900dd6d328da39ab7ebd516abe4025"
+
 /-!
 # Countable types

70d50ecf

feat: add Mathlib.Tactic.Common, and import (#4056)

This makes a mathlib4 version of mathlib3's tactic.basic, now called Mathlib.Tactic.Common, which imports all tactics which do not have significant theory requirements, and then is imported all across the base of the hierarchy.

This ensures that all common tactics are available nearly everywhere in the library, rather than having to be imported one-by-one as you need them.

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

a4eaf1c4

Diff

@@ -9,7 +9,6 @@ Authors: Yury Kudryashov
 ! if you have ported upstream changes.
 -/
 import Mathlib.Data.Finite.Defs
-import Mathlib.Tactic.MkIffOfInductiveProp
 
 /-!
 # Countable types

70d50ecf

chore: add missing #align statements (#1902)

This PR is the result of a slight variant on the following "algorithm"

take all mathlib 3 names, remove _ and make all uppercase letters into lowercase
take all mathlib 4 names, remove _ and make all uppercase letters into lowercase
look for matches, and create pairs (original_lean3_name, OriginalLean4Name)
for pairs that do not have an align statement:
- use Lean 4 to lookup the file + position of the Lean 4 name
- add an #align statement just before the next empty line
manually fix some tiny mistakes (e.g., empty lines in proofs might cause the #align statement to have been inserted too early)

b72bb858

Diff

@@ -53,23 +53,29 @@ protected theorem Function.Injective.countable [Countable β] {f : α → β} (h
   Countable α :=
   let ⟨g, hg⟩ := exists_injective_nat β
   ⟨⟨g ∘ f, hg.comp hf⟩⟩
+#align function.injective.countable Function.Injective.countable
 
 protected theorem Function.Surjective.countable [Countable α] {f : α → β} (hf : Surjective f) :
   Countable β :=
   (injective_surjInv hf).countable
+#align function.surjective.countable Function.Surjective.countable
 
 theorem exists_surjective_nat (α : Sort u) [Nonempty α] [Countable α] : ∃ f : ℕ → α, Surjective f :=
   let ⟨f, hf⟩ := exists_injective_nat α
   ⟨invFun f, invFun_surjective hf⟩
+#align exists_surjective_nat exists_surjective_nat
 
 theorem countable_iff_exists_surjective [Nonempty α] : Countable α ↔ ∃ f : ℕ → α, Surjective f :=
   ⟨@exists_surjective_nat _ _, fun ⟨_, hf⟩ ↦ hf.countable⟩
+#align countable_iff_exists_surjective countable_iff_exists_surjective
 
 theorem Countable.of_equiv (α : Sort _) [Countable α] (e : α ≃ β) : Countable β :=
   e.symm.injective.countable
+#align countable.of_equiv Countable.of_equiv
 
 theorem Equiv.countable_iff (e : α ≃ β) : Countable α ↔ Countable β :=
   ⟨fun h => @Countable.of_equiv _ _ h e, fun h => @Countable.of_equiv _ _ h e.symm⟩
+#align equiv.countable_iff Equiv.countable_iff
 
 instance {β : Type v} [Countable β] : Countable (ULift.{u} β) :=
   Countable.of_equiv _ Equiv.ulift.symm

70d50ecf

Feat: port Data.Set.Countable (#1788)

Co-authored-by: Johan Commelin <johan@commelin.net>

83bdaed2

Diff

@@ -32,12 +32,13 @@ variable {α : Sort u} {β : Sort v}
 ### Definition and basic properties
 -/
 
-
 /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
 @[mk_iff countable_iff_exists_injective]
 class Countable (α : Sort u) : Prop where
   /-- A type `α` is countable if there exists an injective map `α → ℕ`. -/
   exists_injective_nat' : ∃ f : α → ℕ, Injective f
+#align countable Countable
+#align countable_iff_exists_injective countable_iff_exists_injective
 
 lemma Countable.exists_injective_nat (α : Sort u) [Countable α] :
   ∃ f : α → ℕ, Injective f :=

70d50ecf

feat: port Logic.Equiv.List (#1709)

3af1cb32

Diff

@@ -84,7 +84,8 @@ instance [Countable α] : Countable (PLift α) :=
 instance (priority := 100) Subsingleton.to_countable [Subsingleton α] : Countable α :=
   ⟨⟨fun _ => 0, fun x y _ => Subsingleton.elim x y⟩⟩
 
-instance (priority := 500) [Countable α] {p : α → Prop} : Countable { x // p x } :=
+instance (priority := 500) Subtype.countable [Countable α] {p : α → Prop} :
+    Countable { x // p x } :=
   Subtype.val_injective.countable
 
 instance {n : ℕ} : Countable (Fin n) :=
@@ -106,7 +107,8 @@ instance Bool.countable : Countable Bool :=
 instance Prop.countable' : Countable Prop :=
   Countable.of_equiv Bool Equiv.propEquivBool.symm
 
-instance (priority := 500) [Countable α] {r : α → α → Prop} : Countable (Quot r) :=
+instance (priority := 500) Quotient.countable [Countable α] {r : α → α → Prop} :
+    Countable (Quot r) :=
   (surjective_quot_mk r).countable
 
 instance (priority := 500) [Countable α] {s : Setoid α} : Countable (Quotient s) :=

70d50ecf

chore: add source headers to ported theory files (#1094)

The script used to do this is included. The yaml file was obtained from https://raw.githubusercontent.com/wiki/leanprover-community/mathlib/mathlib4-port-status.md

f168625e

Diff

@@ -2,6 +2,11 @@
 Copyright (c) 2022 Yury Kudryashov. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yury Kudryashov
+
+! This file was ported from Lean 3 source module data.countable.defs
+! leanprover-community/mathlib commit 70d50ecfd4900dd6d328da39ab7ebd516abe4025
+! Please do not edit these lines, except to modify the commit id
+! if you have ported upstream changes.
 -/
 import Mathlib.Data.Finite.Defs
 import Mathlib.Tactic.MkIffOfInductiveProp

`data.countable.defs` ⟷ `Mathlib.Data.Countable.Defs`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 18

data.countable.defs ⟷ Mathlib.Data.Countable.Defs

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 18

`data.countable.defs` ⟷ `Mathlib.Data.Countable.Defs`