combinatorics.simple_graph.ends.properties

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

db53863f

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

50251fd6

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 Anand Rao, Rémi Bottinelli. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Anand Rao, Rémi Bottinelli
 -/
-import Mathbin.Combinatorics.SimpleGraph.Ends.Defs
+import Combinatorics.SimpleGraph.Ends.Defs
 
 #align_import combinatorics.simple_graph.ends.properties from "leanprover-community/mathlib"@"50251fd6309cca5ca2e747882ffecd2729f38c5d"

50251fd6

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 Anand Rao, Rémi Bottinelli. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Anand Rao, Rémi Bottinelli
-
-! This file was ported from Lean 3 source module combinatorics.simple_graph.ends.properties
-! leanprover-community/mathlib commit 50251fd6309cca5ca2e747882ffecd2729f38c5d
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Combinatorics.SimpleGraph.Ends.Defs
 
+#align_import combinatorics.simple_graph.ends.properties from "leanprover-community/mathlib"@"50251fd6309cca5ca2e747882ffecd2729f38c5d"
+
 /-!
 # Properties of the ends of graphs

50251fd6

bump to nightly-2023-05-19-03

mathlib commit https://github.com/leanprover-community/mathlib/commit/95a87616d63b3cb49d3fe678d416fbe9c4217bf4

9a2fedb8

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Anand Rao, Rémi Bottinelli
 
 ! This file was ported from Lean 3 source module combinatorics.simple_graph.ends.properties
-! leanprover-community/mathlib commit db53863fb135228820ee0b08e8dce9349a3d911b
+! leanprover-community/mathlib commit 50251fd6309cca5ca2e747882ffecd2729f38c5d
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -13,6 +13,9 @@ import Mathbin.Combinatorics.SimpleGraph.Ends.Defs
 /-!
 # Properties of the ends of graphs
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 This file is meant to contain results about the ends of (locally finite connected) graphs.
 
 -/

db53863f

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

db53863f

feat: infinite (preconnected, locally finite) graphs have nonempty ends (#5916)

Port/review of [mathlib#18410](https://github.com/leanprover-community/mathlib/pull/18410) directly to Mathlib4.

Co-authored-by: Rémi Bottinelli <remi.bottinelli@bluewin.ch> Co-authored-by: Anand Rao <anand.rao.art@gmail.com>

Co-authored-by: Oliver Nash <github@olivernash.org>

e11c53bc

Diff

@@ -4,6 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Anand Rao, Rémi Bottinelli
 -/
 import Mathlib.Combinatorics.SimpleGraph.Ends.Defs
+import Mathlib.CategoryTheory.CofilteredSystem
 
 #align_import combinatorics.simple_graph.ends.properties from "leanprover-community/mathlib"@"db53863fb135228820ee0b08e8dce9349a3d911b"
 
@@ -19,13 +20,31 @@ variable {V : Type} (G : SimpleGraph V)
 
 namespace SimpleGraph
 
-instance [Finite V] : IsEmpty G.end :=
-  ⟨by
+instance [Finite V] : IsEmpty G.end where
+  false := by
     rintro ⟨s, _⟩
     cases nonempty_fintype V
     obtain ⟨v, h⟩ := (s <| Opposite.op Finset.univ).nonempty
-    exact
-      Set.disjoint_iff.mp (s _).disjoint_right
-        ⟨by simp only [Opposite.unop_op, Finset.coe_univ, Set.mem_univ], h⟩⟩
+    exact Set.disjoint_iff.mp (s _).disjoint_right
+        ⟨by simp only [Opposite.unop_op, Finset.coe_univ, Set.mem_univ], h⟩
+
+/-- The `componentCompl`s chosen by an end are all infinite. -/
+lemma end_componentCompl_infinite (e : G.end) (K : (Finset V)ᵒᵖ) :
+    ((e : (j : (Finset V)ᵒᵖ) → G.componentComplFunctor.obj j) K).supp.Infinite := by
+  refine (e.val K).infinite_iff_in_all_ranges.mpr (fun L h => ?_)
+  change Opposite.unop K ⊆ Opposite.unop (Opposite.op L) at h
+  exact ⟨e.val (Opposite.op L), (e.prop (CategoryTheory.opHomOfLE h))⟩
+
+instance compononentComplFunctor_nonempty_of_infinite [Infinite V] (K : (Finset V)ᵒᵖ) :
+    Nonempty (G.componentComplFunctor.obj K) := G.componentCompl_nonempty_of_infinite K.unop
+
+instance componentComplFunctor_finite [LocallyFinite G] [Fact G.Preconnected]
+    (K : (Finset V)ᵒᵖ) : Finite (G.componentComplFunctor.obj K) := G.componentCompl_finite K.unop
+
+/-- A locally finite preconnected infinite graph has at least one end. -/
+lemma nonempty_ends_of_infinite [LocallyFinite G] [Fact G.Preconnected] [Infinite V] :
+    G.end.Nonempty := by
+  classical
+  apply nonempty_sections_of_finite_inverse_system G.componentComplFunctor
 
 end SimpleGraph

db53863f

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 Anand Rao, Rémi Bottinelli. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Anand Rao, Rémi Bottinelli
-
-! This file was ported from Lean 3 source module combinatorics.simple_graph.ends.properties
-! leanprover-community/mathlib commit db53863fb135228820ee0b08e8dce9349a3d911b
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Combinatorics.SimpleGraph.Ends.Defs
 
+#align_import combinatorics.simple_graph.ends.properties from "leanprover-community/mathlib"@"db53863fb135228820ee0b08e8dce9349a3d911b"
+
 /-!
 # Properties of the ends of graphs

db53863f

feat: port Combinatorics.SimpleGraph.Ends.Properties (#4034)

d25807f0

`combinatorics.simple_graph.ends.properties` ⟷ `Mathlib.Combinatorics.SimpleGraph.Ends.Properties`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 8 + 407

combinatorics.simple_graph.ends.properties ⟷ Mathlib.Combinatorics.SimpleGraph.Ends.Properties

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 8 + 407

`combinatorics.simple_graph.ends.properties` ⟷ `Mathlib.Combinatorics.SimpleGraph.Ends.Properties`