combinatorics.derangements.basic | 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

9407b033

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

97eab485

bump to nightly-2024-04-25-08

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

ad7a2212

Diff

@@ -101,7 +101,7 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
     _ ≃ Sum { f : Perm α // fixedPoints f = {a} } { f : Perm α // fixedPoints f = ∅ } :=
       by
       refine' Equiv.sumCongr (subtype_equiv_right fun f => _) (subtype_equiv_right fun f => _)
-      · rw [Set.eq_singleton_iff_unique_mem, and_comm']
+      · rw [Set.eq_singleton_iff_unique_mem, and_comm]
         rfl
       · rw [Set.eq_empty_iff_forall_not_mem]
         refine' ⟨fun h x hx => h.2 (h.1 hx ▸ hx), fun h => ⟨fun x hx => (h _ hx).elim, h _⟩⟩

97eab485

bump to nightly-2024-03-17-08

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

22f01ce4

Diff

@@ -69,7 +69,7 @@ protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
       refine' (perm.subtype_equiv_subtype_perm p).subtypeEquiv fun f => ⟨fun hf a hfa ha => _, _⟩
       · refine' hf ⟨a, ha⟩ (Subtype.ext _)
         rwa [mem_fixed_points, is_fixed_pt, perm.subtype_equiv_subtype_perm, @coeFn_coe_base',
-          Equiv.coe_fn_mk, Subtype.coe_mk, Equiv.Perm.ofSubtype_apply_of_mem] at hfa 
+          Equiv.coe_fn_mk, Subtype.coe_mk, Equiv.Perm.ofSubtype_apply_of_mem] at hfa
       rintro hf ⟨a, ha⟩ hfa
       refine' hf _ _ ha
       change perm.subtype_equiv_subtype_perm p f a = a
@@ -140,7 +140,7 @@ theorem RemoveNone.fiber_none : RemoveNone.fiber (@none α) = ∅ :=
   by
   rw [Set.eq_empty_iff_forall_not_mem]
   intro f hyp
-  rw [remove_none.mem_fiber] at hyp 
+  rw [remove_none.mem_fiber] at hyp
   rcases hyp with ⟨F, F_derangement, F_none, _⟩
   exact F_derangement none F_none
 #align derangements.equiv.remove_none.fiber_none derangements.Equiv.RemoveNone.fiber_none
@@ -156,11 +156,11 @@ theorem RemoveNone.fiber_some (a : α) :
   constructor
   · rw [remove_none.mem_fiber]
     rintro ⟨F, F_derangement, F_none, rfl⟩ x x_fixed
-    rw [mem_fixed_points_iff] at x_fixed 
-    apply_fun some at x_fixed 
+    rw [mem_fixed_points_iff] at x_fixed
+    apply_fun some at x_fixed
     cases' Fx : F (some x) with y
-    · rwa [remove_none_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed 
-    · exfalso; rw [remove_none_some F ⟨y, Fx⟩] at x_fixed ; exact F_derangement _ x_fixed
+    · rwa [remove_none_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed
+    · exfalso; rw [remove_none_some F ⟨y, Fx⟩] at x_fixed; exact F_derangement _ x_fixed
   · intro h_opfp
     use equiv.perm.decompose_option.symm (some a, f)
     constructor

97eab485

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) 2021 Henry Swanson. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Henry Swanson
 -/
-import Mathbin.Dynamics.FixedPoints.Basic
-import Mathbin.GroupTheory.Perm.Option
-import Mathbin.Logic.Equiv.Defs
-import Mathbin.Logic.Equiv.Option
+import Dynamics.FixedPoints.Basic
+import GroupTheory.Perm.Option
+import Logic.Equiv.Defs
+import Logic.Equiv.Option
 
 #align_import combinatorics.derangements.basic from "leanprover-community/mathlib"@"97eab48559068f3d6313da387714ef25768fb730"

97eab485

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) 2021 Henry Swanson. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Henry Swanson
-
-! This file was ported from Lean 3 source module combinatorics.derangements.basic
-! leanprover-community/mathlib commit 97eab48559068f3d6313da387714ef25768fb730
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Dynamics.FixedPoints.Basic
 import Mathbin.GroupTheory.Perm.Option
 import Mathbin.Logic.Equiv.Defs
 import Mathbin.Logic.Equiv.Option
 
+#align_import combinatorics.derangements.basic from "leanprover-community/mathlib"@"97eab48559068f3d6313da387714ef25768fb730"
+
 /-!
 # Derangements on types

97eab485

bump to nightly-2023-06-13-21

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

829520ac

Diff

@@ -208,6 +208,7 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint
 -/
 
+#print derangements.derangementsRecursionEquiv /-
 /-- The set of derangements on `option α` is equivalent to the union over all `a : α` of
     "derangements on `α` ⊕ derangements on `{a}ᶜ`". -/
 def derangementsRecursionEquiv :
@@ -216,6 +217,7 @@ def derangementsRecursionEquiv :
   derangementsOptionEquivSigmaAtMostOneFixedPoint.trans
     (sigmaCongrRight atMostOneFixedPointEquivSum_derangements)
 #align derangements.derangements_recursion_equiv derangements.derangementsRecursionEquiv
+-/
 
 end Option

97eab485

bump to nightly-2023-06-09-07

mathlib commit https://github.com/leanprover-community/mathlib/commit/7e5137f579de09a059a5ce98f364a04e221aabf0

16afdc39

Diff

@@ -82,7 +82,6 @@ protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
     _ ≃ { f : Perm α // ∀ a, ¬p a ↔ a ∈ fixedPoints f } :=
       subtypeEquivRight fun f => by
         simp_rw [exists_prop, ← forall_and, ← iff_iff_implies_and_implies]
-    
 #align derangements.subtype_equiv derangements.subtypeEquiv
 -/
 
@@ -116,7 +115,6 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
           (subtype_equiv_right fun f => mem_derangements_iff_fixed_points_eq_empty.symm)
       rw [eq_comm, Set.ext_iff]
       simp_rw [Set.mem_compl_iff, Classical.not_not]
-    
 #align derangements.at_most_one_fixed_point_equiv_sum_derangements derangements.atMostOneFixedPointEquivSum_derangements
 -/
 
@@ -207,7 +205,6 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
     _ ≃ Σ a : α, ↥(equiv.remove_none.fiber (some a)) :=
       (sigma_option_equiv_of_some _ fiber_none_is_false)
     _ ≃ Σ a : α, {f : perm α | fixed_points f ⊆ {a}} := by simp_rw [equiv.remove_none.fiber_some]
-    
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint
 -/

97eab485

bump to nightly-2023-06-04-18

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

3fb4268b

Diff

@@ -38,7 +38,7 @@ open Equiv Function
 #print derangements /-
 /-- A permutation is a derangement if it has no fixed points. -/
 def derangements (α : Type _) : Set (Perm α) :=
-  { f : Perm α | ∀ x : α, f x ≠ x }
+  {f : Perm α | ∀ x : α, f x ≠ x}
 #align derangements derangements
 -/
 
@@ -128,7 +128,7 @@ variable [DecidableEq α]
 /-- The set of permutations `f` such that the preimage of `(a, f)` under
     `equiv.perm.decompose_option` is a derangement. -/
 def RemoveNone.fiber (a : Option α) : Set (Perm α) :=
-  { f : Perm α | (a, f) ∈ Equiv.Perm.decomposeOption '' derangements (Option α) }
+  {f : Perm α | (a, f) ∈ Equiv.Perm.decomposeOption '' derangements (Option α)}
 #align derangements.equiv.remove_none.fiber derangements.Equiv.RemoveNone.fiber
 -/
 
@@ -155,14 +155,14 @@ theorem RemoveNone.fiber_none : RemoveNone.fiber (@none α) = ∅ :=
 /-- For any `a : α`, the fiber over `some a` is the set of permutations
     where `a` is the only possible fixed point. -/
 theorem RemoveNone.fiber_some (a : α) :
-    RemoveNone.fiber (some a) = { f : Perm α | fixedPoints f ⊆ {a} } :=
+    RemoveNone.fiber (some a) = {f : Perm α | fixedPoints f ⊆ {a}} :=
   by
   ext f
   constructor
   · rw [remove_none.mem_fiber]
     rintro ⟨F, F_derangement, F_none, rfl⟩ x x_fixed
     rw [mem_fixed_points_iff] at x_fixed 
-    apply_fun some  at x_fixed 
+    apply_fun some at x_fixed 
     cases' Fx : F (some x) with y
     · rwa [remove_none_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed 
     · exfalso; rw [remove_none_some F ⟨y, Fx⟩] at x_fixed ; exact F_derangement _ x_fixed
@@ -196,7 +196,7 @@ variable [DecidableEq α]
 /-- The set of derangements on `option α` is equivalent to the union over `a : α`
     of "permutations with `a` the only possible fixed point". -/
 def derangementsOptionEquivSigmaAtMostOneFixedPoint :
-    derangements (Option α) ≃ Σ a : α, { f : Perm α | fixedPoints f ⊆ {a} } :=
+    derangements (Option α) ≃ Σ a : α, {f : Perm α | fixedPoints f ⊆ {a}} :=
   by
   have fiber_none_is_false : equiv.remove_none.fiber (@none α) → False := by
     rw [equiv.remove_none.fiber_none]; exact IsEmpty.false
@@ -206,7 +206,7 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
     _ ≃ Σ a : Option α, ↥(equiv.remove_none.fiber a) := (set_prod_equiv_sigma _)
     _ ≃ Σ a : α, ↥(equiv.remove_none.fiber (some a)) :=
       (sigma_option_equiv_of_some _ fiber_none_is_false)
-    _ ≃ Σ a : α, { f : perm α | fixed_points f ⊆ {a} } := by simp_rw [equiv.remove_none.fiber_some]
+    _ ≃ Σ a : α, {f : perm α | fixed_points f ⊆ {a}} := by simp_rw [equiv.remove_none.fiber_some]
     
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint
 -/

97eab485

bump to nightly-2023-06-01-16

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

b9c87c70

Diff

@@ -72,7 +72,7 @@ protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
       refine' (perm.subtype_equiv_subtype_perm p).subtypeEquiv fun f => ⟨fun hf a hfa ha => _, _⟩
       · refine' hf ⟨a, ha⟩ (Subtype.ext _)
         rwa [mem_fixed_points, is_fixed_pt, perm.subtype_equiv_subtype_perm, @coeFn_coe_base',
-          Equiv.coe_fn_mk, Subtype.coe_mk, Equiv.Perm.ofSubtype_apply_of_mem] at hfa
+          Equiv.coe_fn_mk, Subtype.coe_mk, Equiv.Perm.ofSubtype_apply_of_mem] at hfa 
       rintro hf ⟨a, ha⟩ hfa
       refine' hf _ _ ha
       change perm.subtype_equiv_subtype_perm p f a = a
@@ -145,7 +145,7 @@ theorem RemoveNone.fiber_none : RemoveNone.fiber (@none α) = ∅ :=
   by
   rw [Set.eq_empty_iff_forall_not_mem]
   intro f hyp
-  rw [remove_none.mem_fiber] at hyp
+  rw [remove_none.mem_fiber] at hyp 
   rcases hyp with ⟨F, F_derangement, F_none, _⟩
   exact F_derangement none F_none
 #align derangements.equiv.remove_none.fiber_none derangements.Equiv.RemoveNone.fiber_none
@@ -161,11 +161,11 @@ theorem RemoveNone.fiber_some (a : α) :
   constructor
   · rw [remove_none.mem_fiber]
     rintro ⟨F, F_derangement, F_none, rfl⟩ x x_fixed
-    rw [mem_fixed_points_iff] at x_fixed
-    apply_fun some  at x_fixed
+    rw [mem_fixed_points_iff] at x_fixed 
+    apply_fun some  at x_fixed 
     cases' Fx : F (some x) with y
-    · rwa [remove_none_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed
-    · exfalso; rw [remove_none_some F ⟨y, Fx⟩] at x_fixed; exact F_derangement _ x_fixed
+    · rwa [remove_none_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed 
+    · exfalso; rw [remove_none_some F ⟨y, Fx⟩] at x_fixed ; exact F_derangement _ x_fixed
   · intro h_opfp
     use equiv.perm.decompose_option.symm (some a, f)
     constructor
@@ -196,17 +196,17 @@ variable [DecidableEq α]
 /-- The set of derangements on `option α` is equivalent to the union over `a : α`
     of "permutations with `a` the only possible fixed point". -/
 def derangementsOptionEquivSigmaAtMostOneFixedPoint :
-    derangements (Option α) ≃ Σa : α, { f : Perm α | fixedPoints f ⊆ {a} } :=
+    derangements (Option α) ≃ Σ a : α, { f : Perm α | fixedPoints f ⊆ {a} } :=
   by
   have fiber_none_is_false : equiv.remove_none.fiber (@none α) → False := by
     rw [equiv.remove_none.fiber_none]; exact IsEmpty.false
   calc
     derangements (Option α) ≃ Equiv.Perm.decomposeOption '' derangements (Option α) :=
       Equiv.image _ _
-    _ ≃ Σa : Option α, ↥(equiv.remove_none.fiber a) := (set_prod_equiv_sigma _)
-    _ ≃ Σa : α, ↥(equiv.remove_none.fiber (some a)) :=
+    _ ≃ Σ a : Option α, ↥(equiv.remove_none.fiber a) := (set_prod_equiv_sigma _)
+    _ ≃ Σ a : α, ↥(equiv.remove_none.fiber (some a)) :=
       (sigma_option_equiv_of_some _ fiber_none_is_false)
-    _ ≃ Σa : α, { f : perm α | fixed_points f ⊆ {a} } := by simp_rw [equiv.remove_none.fiber_some]
+    _ ≃ Σ a : α, { f : perm α | fixed_points f ⊆ {a} } := by simp_rw [equiv.remove_none.fiber_some]
     
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint
 -/
@@ -215,7 +215,7 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
     "derangements on `α` ⊕ derangements on `{a}ᶜ`". -/
 def derangementsRecursionEquiv :
     derangements (Option α) ≃
-      Σa : α, Sum (derangements (({a}ᶜ : Set α) : Type _)) (derangements α) :=
+      Σ a : α, Sum (derangements (({a}ᶜ : Set α) : Type _)) (derangements α) :=
   derangementsOptionEquivSigmaAtMostOneFixedPoint.trans
     (sigmaCongrRight atMostOneFixedPointEquivSum_derangements)
 #align derangements.derangements_recursion_equiv derangements.derangementsRecursionEquiv

97eab485

bump to nightly-2023-05-28-06

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

ba5d8b97

Diff

@@ -211,12 +211,6 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint
 -/
 
-/- warning: derangements.derangements_recursion_equiv -> derangements.derangementsRecursionEquiv is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α], Equiv.{succ u1, succ u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} (Equiv.Perm.{succ u1} (Option.{u1} α))) Type.{u1} (Set.hasCoeToSort.{u1} (Equiv.Perm.{succ u1} (Option.{u1} α))) (derangements.{u1} (Option.{u1} α))) (Sigma.{u1, u1} α (fun (a : α) => Sum.{u1, u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} (Equiv.Perm.{succ u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} α) Type.{u1} (Set.hasCoeToSort.{u1} α) (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.booleanAlgebra.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.hasSingleton.{u1} α) a))))) Type.{u1} (Set.hasCoeToSort.{u1} (Equiv.Perm.{succ u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} α) Type.{u1} (Set.hasCoeToSort.{u1} α) (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.booleanAlgebra.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.hasSingleton.{u1} α) a))))) (derangements.{u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} α) Type.{u1} (Set.hasCoeToSort.{u1} α) (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.booleanAlgebra.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.hasSingleton.{u1} α) a))))) (coeSort.{succ u1, succ (succ u1)} (Set.{u1} (Equiv.Perm.{succ u1} α)) Type.{u1} (Set.hasCoeToSort.{u1} (Equiv.Perm.{succ u1} α)) (derangements.{u1} α))))
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α], Equiv.{succ u1, succ u1} (Set.Elem.{u1} (Equiv.Perm.{succ u1} (Option.{u1} α)) (derangements.{u1} (Option.{u1} α))) (Sigma.{u1, u1} α (fun (a : α) => Sum.{u1, u1} (Set.Elem.{u1} (Equiv.Perm.{succ u1} (Set.Elem.{u1} α (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.instBooleanAlgebraSet.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.instSingletonSet.{u1} α) a)))) (derangements.{u1} (Set.Elem.{u1} α (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.instBooleanAlgebraSet.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.instSingletonSet.{u1} α) a))))) (Set.Elem.{u1} (Equiv.Perm.{succ u1} α) (derangements.{u1} α))))
-Case conversion may be inaccurate. Consider using '#align derangements.derangements_recursion_equiv derangements.derangementsRecursionEquivₓ'. -/
 /-- The set of derangements on `option α` is equivalent to the union over all `a : α` of
     "derangements on `α` ⊕ derangements on `{a}ᶜ`". -/
 def derangementsRecursionEquiv :

97eab485

bump to nightly-2023-05-28-04

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

6797a637

Diff

@@ -101,10 +101,7 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
         Sum { f : Perm α // fixedPoints f ⊆ {a} ∧ a ∈ fixedPoints f }
           { f : Perm α // fixedPoints f ⊆ {a} ∧ a ∉ fixedPoints f } :=
       by
-      refine' Equiv.sumCongr _ _ <;>
-        · convert subtype_subtype_equiv_subtype_inter _ _
-          ext f
-          rfl
+      refine' Equiv.sumCongr _ _ <;> · convert subtype_subtype_equiv_subtype_inter _ _; ext f; rfl
     _ ≃ Sum { f : Perm α // fixedPoints f = {a} } { f : Perm α // fixedPoints f = ∅ } :=
       by
       refine' Equiv.sumCongr (subtype_equiv_right fun f => _) (subtype_equiv_right fun f => _)
@@ -168,9 +165,7 @@ theorem RemoveNone.fiber_some (a : α) :
     apply_fun some  at x_fixed
     cases' Fx : F (some x) with y
     · rwa [remove_none_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed
-    · exfalso
-      rw [remove_none_some F ⟨y, Fx⟩] at x_fixed
-      exact F_derangement _ x_fixed
+    · exfalso; rw [remove_none_some F ⟨y, Fx⟩] at x_fixed; exact F_derangement _ x_fixed
   · intro h_opfp
     use equiv.perm.decompose_option.symm (some a, f)
     constructor
@@ -181,8 +176,7 @@ theorem RemoveNone.fiber_some (a : α) :
       · simp
       simp only [Equiv.optionCongr_apply, Option.map_some']
       by_cases x_vs_a : x = a
-      · rw [x_vs_a, swap_apply_right]
-        apply Option.some_ne_none
+      · rw [x_vs_a, swap_apply_right]; apply Option.some_ne_none
       have ne_1 : some x ≠ none := Option.some_ne_none _
       have ne_2 : some x ≠ some a := (Option.some_injective α).ne_iff.mpr x_vs_a
       rw [swap_apply_of_ne_of_ne ne_1 ne_2, (Option.some_injective α).ne_iff]
@@ -204,10 +198,8 @@ variable [DecidableEq α]
 def derangementsOptionEquivSigmaAtMostOneFixedPoint :
     derangements (Option α) ≃ Σa : α, { f : Perm α | fixedPoints f ⊆ {a} } :=
   by
-  have fiber_none_is_false : equiv.remove_none.fiber (@none α) → False :=
-    by
-    rw [equiv.remove_none.fiber_none]
-    exact IsEmpty.false
+  have fiber_none_is_false : equiv.remove_none.fiber (@none α) → False := by
+    rw [equiv.remove_none.fiber_none]; exact IsEmpty.false
   calc
     derangements (Option α) ≃ Equiv.Perm.decomposeOption '' derangements (Option α) :=
       Equiv.image _ _

97eab485

bump to nightly-2023-03-25-02

mathlib commit https://github.com/leanprover-community/mathlib/commit/d11893b411025250c8e61ff2f12ccbd7ee35ab15

9ce440f0

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Henry Swanson
 
 ! This file was ported from Lean 3 source module combinatorics.derangements.basic
-! leanprover-community/mathlib commit 9407b03373c8cd201df99d6bc5514fc2db44054f
+! leanprover-community/mathlib commit 97eab48559068f3d6313da387714ef25768fb730
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -16,6 +16,9 @@ import Mathbin.Logic.Equiv.Option
 /-!
 # Derangements on types
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 In this file we define `derangements α`, the set of derangements on a type `α`.
 
 We also define some equivalences involving various subtypes of `perm α` and `derangements α`:

9407b033

bump to nightly-2023-03-23-20

mathlib commit https://github.com/leanprover-community/mathlib/commit/57e09a1296bfb4330ddf6624f1028ba186117d82

53b827ba

Diff

@@ -32,25 +32,32 @@ on derangements: `remove_none.fiber_none` and `remove_none.fiber_some`.
 
 open Equiv Function
 
+#print derangements /-
 /-- A permutation is a derangement if it has no fixed points. -/
 def derangements (α : Type _) : Set (Perm α) :=
   { f : Perm α | ∀ x : α, f x ≠ x }
 #align derangements derangements
+-/
 
 variable {α β : Type _}
 
+#print mem_derangements_iff_fixedPoints_eq_empty /-
 theorem mem_derangements_iff_fixedPoints_eq_empty {f : Perm α} :
     f ∈ derangements α ↔ fixedPoints f = ∅ :=
   Set.eq_empty_iff_forall_not_mem.symm
 #align mem_derangements_iff_fixed_points_eq_empty mem_derangements_iff_fixedPoints_eq_empty
+-/
 
+#print Equiv.derangementsCongr /-
 /-- If `α` is equivalent to `β`, then `derangements α` is equivalent to `derangements β`. -/
 def Equiv.derangementsCongr (e : α ≃ β) : derangements α ≃ derangements β :=
   e.permCongr.subtypeEquiv fun f => e.forall_congr' <| by simp
 #align equiv.derangements_congr Equiv.derangementsCongr
+-/
 
 namespace derangements
 
+#print derangements.subtypeEquiv /-
 /-- Derangements on a subtype are equivalent to permutations on the original type where points are
 fixed iff they are not in the subtype. -/
 protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
@@ -74,11 +81,13 @@ protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
         simp_rw [exists_prop, ← forall_and, ← iff_iff_implies_and_implies]
     
 #align derangements.subtype_equiv derangements.subtypeEquiv
+-/
 
+#print derangements.atMostOneFixedPointEquivSum_derangements /-
 /-- The set of permutations that fix either `a` or nothing is equivalent to the sum of:
     - derangements on `α`
     - derangements on `α` minus `a`. -/
-def atMostOneFixedPointEquivSumDerangements [DecidableEq α] (a : α) :
+def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
     { f : Perm α // fixedPoints f ⊆ {a} } ≃ Sum (derangements ({a}ᶜ : Set α)) (derangements α) :=
   calc
     { f : Perm α // fixedPoints f ⊆ {a} } ≃
@@ -108,24 +117,30 @@ def atMostOneFixedPointEquivSumDerangements [DecidableEq α] (a : α) :
       rw [eq_comm, Set.ext_iff]
       simp_rw [Set.mem_compl_iff, Classical.not_not]
     
-#align derangements.at_most_one_fixed_point_equiv_sum_derangements derangements.atMostOneFixedPointEquivSumDerangements
+#align derangements.at_most_one_fixed_point_equiv_sum_derangements derangements.atMostOneFixedPointEquivSum_derangements
+-/
 
 namespace Equiv
 
 variable [DecidableEq α]
 
+#print derangements.Equiv.RemoveNone.fiber /-
 /-- The set of permutations `f` such that the preimage of `(a, f)` under
     `equiv.perm.decompose_option` is a derangement. -/
 def RemoveNone.fiber (a : Option α) : Set (Perm α) :=
   { f : Perm α | (a, f) ∈ Equiv.Perm.decomposeOption '' derangements (Option α) }
 #align derangements.equiv.remove_none.fiber derangements.Equiv.RemoveNone.fiber
+-/
 
+#print derangements.Equiv.RemoveNone.mem_fiber /-
 theorem RemoveNone.mem_fiber (a : Option α) (f : Perm α) :
     f ∈ RemoveNone.fiber a ↔
       ∃ F : Perm (Option α), F ∈ derangements (Option α) ∧ F none = a ∧ removeNone F = f :=
   by simp [remove_none.fiber, derangements]
 #align derangements.equiv.remove_none.mem_fiber derangements.Equiv.RemoveNone.mem_fiber
+-/
 
+#print derangements.Equiv.RemoveNone.fiber_none /-
 theorem RemoveNone.fiber_none : RemoveNone.fiber (@none α) = ∅ :=
   by
   rw [Set.eq_empty_iff_forall_not_mem]
@@ -134,7 +149,9 @@ theorem RemoveNone.fiber_none : RemoveNone.fiber (@none α) = ∅ :=
   rcases hyp with ⟨F, F_derangement, F_none, _⟩
   exact F_derangement none F_none
 #align derangements.equiv.remove_none.fiber_none derangements.Equiv.RemoveNone.fiber_none
+-/
 
+#print derangements.Equiv.RemoveNone.fiber_some /-
 /-- For any `a : α`, the fiber over `some a` is the set of permutations
     where `a` is the only possible fixed point. -/
 theorem RemoveNone.fiber_some (a : α) :
@@ -170,6 +187,7 @@ theorem RemoveNone.fiber_some (a : α) :
       exact x_vs_a (h_opfp contra)
     · rw [apply_symm_apply]
 #align derangements.equiv.remove_none.fiber_some derangements.Equiv.RemoveNone.fiber_some
+-/
 
 end Equiv
 
@@ -177,6 +195,7 @@ section Option
 
 variable [DecidableEq α]
 
+#print derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint /-
 /-- The set of derangements on `option α` is equivalent to the union over `a : α`
     of "permutations with `a` the only possible fixed point". -/
 def derangementsOptionEquivSigmaAtMostOneFixedPoint :
@@ -195,14 +214,21 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
     _ ≃ Σa : α, { f : perm α | fixed_points f ⊆ {a} } := by simp_rw [equiv.remove_none.fiber_some]
     
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint
+-/
 
+/- warning: derangements.derangements_recursion_equiv -> derangements.derangementsRecursionEquiv is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α], Equiv.{succ u1, succ u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} (Equiv.Perm.{succ u1} (Option.{u1} α))) Type.{u1} (Set.hasCoeToSort.{u1} (Equiv.Perm.{succ u1} (Option.{u1} α))) (derangements.{u1} (Option.{u1} α))) (Sigma.{u1, u1} α (fun (a : α) => Sum.{u1, u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} (Equiv.Perm.{succ u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} α) Type.{u1} (Set.hasCoeToSort.{u1} α) (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.booleanAlgebra.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.hasSingleton.{u1} α) a))))) Type.{u1} (Set.hasCoeToSort.{u1} (Equiv.Perm.{succ u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} α) Type.{u1} (Set.hasCoeToSort.{u1} α) (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.booleanAlgebra.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.hasSingleton.{u1} α) a))))) (derangements.{u1} (coeSort.{succ u1, succ (succ u1)} (Set.{u1} α) Type.{u1} (Set.hasCoeToSort.{u1} α) (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.booleanAlgebra.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.hasSingleton.{u1} α) a))))) (coeSort.{succ u1, succ (succ u1)} (Set.{u1} (Equiv.Perm.{succ u1} α)) Type.{u1} (Set.hasCoeToSort.{u1} (Equiv.Perm.{succ u1} α)) (derangements.{u1} α))))
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α], Equiv.{succ u1, succ u1} (Set.Elem.{u1} (Equiv.Perm.{succ u1} (Option.{u1} α)) (derangements.{u1} (Option.{u1} α))) (Sigma.{u1, u1} α (fun (a : α) => Sum.{u1, u1} (Set.Elem.{u1} (Equiv.Perm.{succ u1} (Set.Elem.{u1} α (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.instBooleanAlgebraSet.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.instSingletonSet.{u1} α) a)))) (derangements.{u1} (Set.Elem.{u1} α (HasCompl.compl.{u1} (Set.{u1} α) (BooleanAlgebra.toHasCompl.{u1} (Set.{u1} α) (Set.instBooleanAlgebraSet.{u1} α)) (Singleton.singleton.{u1, u1} α (Set.{u1} α) (Set.instSingletonSet.{u1} α) a))))) (Set.Elem.{u1} (Equiv.Perm.{succ u1} α) (derangements.{u1} α))))
+Case conversion may be inaccurate. Consider using '#align derangements.derangements_recursion_equiv derangements.derangementsRecursionEquivₓ'. -/
 /-- The set of derangements on `option α` is equivalent to the union over all `a : α` of
     "derangements on `α` ⊕ derangements on `{a}ᶜ`". -/
 def derangementsRecursionEquiv :
     derangements (Option α) ≃
       Σa : α, Sum (derangements (({a}ᶜ : Set α) : Type _)) (derangements α) :=
   derangementsOptionEquivSigmaAtMostOneFixedPoint.trans
-    (sigmaCongrRight atMostOneFixedPointEquivSumDerangements)
+    (sigmaCongrRight atMostOneFixedPointEquivSum_derangements)
 #align derangements.derangements_recursion_equiv derangements.derangementsRecursionEquiv
 
 end Option

9407b033

bump to nightly-2023-03-01-20

mathlib commit https://github.com/leanprover-community/mathlib/commit/4c586d291f189eecb9d00581aeb3dd998ac34442

20cadee0

Diff

@@ -68,7 +68,7 @@ protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
       change perm.subtype_equiv_subtype_perm p f a = a
       rw [perm.subtype_equiv_subtype_perm_apply_of_mem f ha, hfa, Subtype.coe_mk]
     _ ≃ { f : Perm α // ∃ h : ∀ a, ¬p a → a ∈ fixedPoints f, ∀ a, a ∈ fixedPoints f → ¬p a } :=
-      subtypeSubtypeEquivSubtypeExists _ _
+      (subtypeSubtypeEquivSubtypeExists _ _)
     _ ≃ { f : Perm α // ∀ a, ¬p a ↔ a ∈ fixedPoints f } :=
       subtypeEquivRight fun f => by
         simp_rw [exists_prop, ← forall_and, ← iff_iff_implies_and_implies]
@@ -189,9 +189,9 @@ def derangementsOptionEquivSigmaAtMostOneFixedPoint :
   calc
     derangements (Option α) ≃ Equiv.Perm.decomposeOption '' derangements (Option α) :=
       Equiv.image _ _
-    _ ≃ Σa : Option α, ↥(equiv.remove_none.fiber a) := set_prod_equiv_sigma _
+    _ ≃ Σa : Option α, ↥(equiv.remove_none.fiber a) := (set_prod_equiv_sigma _)
     _ ≃ Σa : α, ↥(equiv.remove_none.fiber (some a)) :=
-      sigma_option_equiv_of_some _ fiber_none_is_false
+      (sigma_option_equiv_of_some _ fiber_none_is_false)
     _ ≃ Σa : α, { f : perm α | fixed_points f ⊆ {a} } := by simp_rw [equiv.remove_none.fiber_some]
     
 #align derangements.derangements_option_equiv_sigma_at_most_one_fixed_point derangements.derangementsOptionEquivSigmaAtMostOneFixedPoint

9407b033

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

9407b033

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

@@ -86,7 +86,7 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
       (Equiv.sumCompl _).symm
     _ ≃ Sum { f : Perm α // fixedPoints f ⊆ {a} ∧ a ∈ fixedPoints f }
           { f : Perm α // fixedPoints f ⊆ {a} ∧ a ∉ fixedPoints f } := by
-      -- porting note: `subtypeSubtypeEquivSubtypeInter` no longer works with placeholder `_`s.
+      -- Porting note: `subtypeSubtypeEquivSubtypeInter` no longer works with placeholder `_`s.
       refine' Equiv.sumCongr _ _
       · exact subtypeSubtypeEquivSubtypeInter
           (fun x : Perm α => fixedPoints x ⊆ {a})
@@ -101,7 +101,7 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
       · rw [Set.eq_empty_iff_forall_not_mem]
         exact ⟨fun h x hx => h.2 (h.1 hx ▸ hx), fun h => ⟨fun x hx => (h _ hx).elim, h _⟩⟩
     _ ≃ Sum (derangements ({a}ᶜ : Set α)) (derangements α) := by
-      -- porting note: was `subtypeEquiv _` but now needs the placeholder to be provided explicitly
+      -- Porting note: was `subtypeEquiv _` but now needs the placeholder to be provided explicitly
       refine'
         Equiv.sumCongr ((derangements.subtypeEquiv (· ∈ ({a}ᶜ : Set α))).trans <|
             subtypeEquivRight fun x => _).symm

9407b033

chore: remove terminal, terminal refines (#10762)

I replaced a few "terminal" refine/refine's with exact.

The strategy was very simple-minded: essentially any refine whose following line had smaller indentation got replaced by exact and then I cleaned up the mess.

This PR certainly leaves some further terminal refines, but maybe the current change is beneficial.

ea36aa7d

Diff

@@ -99,7 +99,7 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
       · rw [Set.eq_singleton_iff_unique_mem, and_comm]
         rfl
       · rw [Set.eq_empty_iff_forall_not_mem]
-        refine' ⟨fun h x hx => h.2 (h.1 hx ▸ hx), fun h => ⟨fun x hx => (h _ hx).elim, h _⟩⟩
+        exact ⟨fun h x hx => h.2 (h.1 hx ▸ hx), fun h => ⟨fun x hx => (h _ hx).elim, h _⟩⟩
     _ ≃ Sum (derangements ({a}ᶜ : Set α)) (derangements α) := by
       -- porting note: was `subtypeEquiv _` but now needs the placeholder to be provided explicitly
       refine'

9407b033

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

@@ -19,7 +19,7 @@ We also define some equivalences involving various subtypes of `Perm α` and `de
 * `derangementsOptionEquivSigmaAtMostOneFixedPoint`: An equivalence between
   `derangements (Option α)` and the sigma-type `Σ a : α, {f : Perm α // fixed_points f ⊆ a}`.
 * `derangementsRecursionEquiv`: An equivalence between `derangements (Option α)` and the
-  sigma-type `Σ a : α, (derangements (({a}ᶜ : Set α) : Type _) ⊕ derangements α)` which is later
+  sigma-type `Σ a : α, (derangements (({a}ᶜ : Set α) : Type*) ⊕ derangements α)` which is later
   used to inductively count the number of derangements.
 
 In order to prove the above, we also prove some results about the effect of `Equiv.removeNone`
@@ -30,11 +30,11 @@ on derangements: `RemoveNone.fiber_none` and `RemoveNone.fiber_some`.
 open Equiv Function
 
 /-- A permutation is a derangement if it has no fixed points. -/
-def derangements (α : Type _) : Set (Perm α) :=
+def derangements (α : Type*) : Set (Perm α) :=
   { f : Perm α | ∀ x : α, f x ≠ x }
 #align derangements derangements
 
-variable {α β : Type _}
+variable {α β : Type*}
 
 theorem mem_derangements_iff_fixedPoints_eq_empty {f : Perm α} :
     f ∈ derangements α ↔ fixedPoints f = ∅ :=

9407b033

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) 2021 Henry Swanson. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Henry Swanson
-
-! This file was ported from Lean 3 source module combinatorics.derangements.basic
-! leanprover-community/mathlib commit 9407b03373c8cd201df99d6bc5514fc2db44054f
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Dynamics.FixedPoints.Basic
 import Mathlib.GroupTheory.Perm.Option
 import Mathlib.Logic.Equiv.Defs
 import Mathlib.Logic.Equiv.Option
 
+#align_import combinatorics.derangements.basic from "leanprover-community/mathlib"@"9407b03373c8cd201df99d6bc5514fc2db44054f"
+
 /-!
 # Derangements on types

9407b033

chore: fix focusing dots (#5708)

This PR is the result of running

find . -type f -name "*.lean" -exec sed -i -E 's/^( +)\. /\1· /' {} \;
find . -type f -name "*.lean" -exec sed -i -E 'N;s/^( +·)\n +(.*)$/\1 \2/;P;D' {} \;

which firstly replaces . focusing dots with · and secondly removes isolated instances of such dots, unifying them with the following line. A new rule is placed in the style linter to verify this.

cb02d09e

Diff

@@ -91,10 +91,10 @@ def atMostOneFixedPointEquivSum_derangements [DecidableEq α] (a : α) :
           { f : Perm α // fixedPoints f ⊆ {a} ∧ a ∉ fixedPoints f } := by
       -- porting note: `subtypeSubtypeEquivSubtypeInter` no longer works with placeholder `_`s.
       refine' Equiv.sumCongr _ _
-      . exact subtypeSubtypeEquivSubtypeInter
+      · exact subtypeSubtypeEquivSubtypeInter
           (fun x : Perm α => fixedPoints x ⊆ {a})
           (a ∈ fixedPoints ·)
-      . exact subtypeSubtypeEquivSubtypeInter
+      · exact subtypeSubtypeEquivSubtypeInter
           (fun x : Perm α => fixedPoints x ⊆ {a})
           (¬a ∈ fixedPoints ·)
     _ ≃ Sum { f : Perm α // fixedPoints f = {a} } { f : Perm α // fixedPoints f = ∅ } := by

9407b033

chore: clean up spacing around at and goals (#5387)

Changes are of the form

some_tactic at h⊢ -> some_tactic at h ⊢
some_tactic at h -> some_tactic at h

2a870323

Diff

@@ -146,7 +146,7 @@ theorem RemoveNone.fiber_some (a : α) :
   · rw [RemoveNone.mem_fiber]
     rintro ⟨F, F_derangement, F_none, rfl⟩ x x_fixed
     rw [mem_fixedPoints_iff] at x_fixed
-    apply_fun some  at x_fixed
+    apply_fun some at x_fixed
     cases' Fx : F (some x) with y
     · rwa [removeNone_none F Fx, F_none, Option.some_inj, eq_comm] at x_fixed
     · exfalso

9407b033

chore: bye-bye, solo bys! (#3825)

This PR puts, with one exception, every single remaining by that lies all by itself on its own line to the previous line, thus matching the current behaviour of start-port.sh. The exception is when the by begins the second or later argument to a tuple or anonymous constructor; see https://github.com/leanprover-community/mathlib4/pull/3825#discussion_r1186702599.

Essentially this is s/\n *by$/ by/g, but with manual editing to satisfy the linter's max-100-char-line requirement. The Python style linter is also modified to catch these "isolated bys".

14167e48

Diff

@@ -57,19 +57,18 @@ fixed iff they are not in the subtype. -/
 protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
     derangements (Subtype p) ≃ { f : Perm α // ∀ a, ¬p a ↔ a ∈ fixedPoints f } :=
   calc
-    derangements (Subtype p) ≃
-        { f : { f : Perm α // ∀ a, ¬p a → a ∈ fixedPoints f } // ∀ a, a ∈ fixedPoints f → ¬p a } :=
-      by
-        refine' (Perm.subtypeEquivSubtypePerm p).subtypeEquiv fun f => ⟨fun hf a hfa ha => _, _⟩
-        · refine' hf ⟨a, ha⟩ (Subtype.ext _)
-          simp_rw [mem_fixedPoints, IsFixedPt, Perm.subtypeEquivSubtypePerm,
-          Equiv.coe_fn_mk, Perm.ofSubtype_apply_of_mem _ ha] at hfa
-          assumption
-        rintro hf ⟨a, ha⟩ hfa
-        refine' hf _ _ ha
-        simp only [Perm.subtypeEquivSubtypePerm_apply_coe, mem_fixedPoints]
-        dsimp [IsFixedPt]
-        simp_rw [Perm.ofSubtype_apply_of_mem _ ha, hfa]
+    derangements (Subtype p) ≃ { f : { f : Perm α // ∀ a, ¬p a → a ∈ fixedPoints f } //
+        ∀ a, a ∈ fixedPoints f → ¬p a } := by
+      refine' (Perm.subtypeEquivSubtypePerm p).subtypeEquiv fun f => ⟨fun hf a hfa ha => _, _⟩
+      · refine' hf ⟨a, ha⟩ (Subtype.ext _)
+        simp_rw [mem_fixedPoints, IsFixedPt, Perm.subtypeEquivSubtypePerm,
+        Equiv.coe_fn_mk, Perm.ofSubtype_apply_of_mem _ ha] at hfa
+        assumption
+      rintro hf ⟨a, ha⟩ hfa
+      refine' hf _ _ ha
+      simp only [Perm.subtypeEquivSubtypePerm_apply_coe, mem_fixedPoints]
+      dsimp [IsFixedPt]
+      simp_rw [Perm.ofSubtype_apply_of_mem _ ha, hfa]
     _ ≃ { f : Perm α // ∃ _h : ∀ a, ¬p a → a ∈ fixedPoints f, ∀ a, a ∈ fixedPoints f → ¬p a } :=
       subtypeSubtypeEquivSubtypeExists _ _
     _ ≃ { f : Perm α // ∀ a, ¬p a ↔ a ∈ fixedPoints f } :=
@@ -183,8 +182,7 @@ variable [DecidableEq α]
     of "permutations with `a` the only possible fixed point". -/
 def derangementsOptionEquivSigmaAtMostOneFixedPoint :
     derangements (Option α) ≃ Σa : α, { f : Perm α | fixedPoints f ⊆ {a} } := by
-  have fiber_none_is_false : Equiv.RemoveNone.fiber (@none α) → False :=
-    by
+  have fiber_none_is_false : Equiv.RemoveNone.fiber (@none α) → False := by
     rw [Equiv.RemoveNone.fiber_none]
     exact IsEmpty.false
   calc

9407b033

feat: implement intermediate state for simp_rw (#3738)

closes #3680, see https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/Stepping.20through.20simp_rw/near/326712986

ff334843

Diff

@@ -63,7 +63,7 @@ protected def subtypeEquiv (p : α → Prop) [DecidablePred p] :
         refine' (Perm.subtypeEquivSubtypePerm p).subtypeEquiv fun f => ⟨fun hf a hfa ha => _, _⟩
         · refine' hf ⟨a, ha⟩ (Subtype.ext _)
           simp_rw [mem_fixedPoints, IsFixedPt, Perm.subtypeEquivSubtypePerm,
-          Equiv.coe_fn_mk, Subtype.coe_mk, Perm.ofSubtype_apply_of_mem _ ha] at hfa
+          Equiv.coe_fn_mk, Perm.ofSubtype_apply_of_mem _ ha] at hfa
           assumption
         rintro hf ⟨a, ha⟩ hfa
         refine' hf _ _ ha

9407b033

feat: Port/Combinatorics.Derangements.Basic (#2530)

Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: ChrisHughes24 <chrishughes24@gmail.com>

19cc4324

`combinatorics.derangements.basic` ⟷ `Mathlib.Combinatorics.Derangements.Basic`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 8 + 373

combinatorics.derangements.basic ⟷ Mathlib.Combinatorics.Derangements.Basic

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 8 + 373

`combinatorics.derangements.basic` ⟷ `Mathlib.Combinatorics.Derangements.Basic`