dynamics.ergodic.add_circle | 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

5f6e827d

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

f2ad3645

bump to nightly-2024-04-06-08

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

e34029c9

Diff

@@ -102,7 +102,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     by
     rw [volume_closed_ball, mul_div, mul_div_mul_left T _ two_ne_zero,
       min_eq_right (div_le_self hT₀.le huj'), mul_comm, ← nsmul_eq_mul, ← ENNReal.ofReal_nsmul,
-      nsmul_eq_mul, mul_div_cancel']
+      nsmul_eq_mul, mul_div_cancel₀]
     exact nat.cast_ne_zero.mpr hj.ne'
   rw [ENNReal.div_eq_div_iff hT₁ ENNReal.ofReal_ne_top hI₀ hI₁,
     volume_of_add_preimage_eq s _ (u j) d huj (hu₁ j) closed_ball_ae_eq_ball, nsmul_eq_mul, ←
@@ -120,7 +120,7 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
       have hu₀ : ∀ j, addOrderOf (u j) = n.nat_abs ^ j := fun j =>
         add_order_of_div_of_gcd_eq_one (pow_pos (pos_of_gt hn) j) (gcd_one_left _)
       have hnu : ∀ j, n ^ j • u j = 0 := fun j => by
-        rw [← addOrderOf_dvd_iff_zsmul_eq_zero, hu₀, Int.coe_nat_pow, Int.coe_natAbs, ← abs_pow,
+        rw [← addOrderOf_dvd_iff_zsmul_eq_zero, hu₀, Int.coe_nat_pow, Int.natCast_natAbs, ← abs_pow,
           abs_dvd]
       have hu₁ : ∀ j, (u j +ᵥ s : Set _) =ᵐ[volume] s := fun j => by
         rw [vadd_eq_self_of_preimage_zsmul_eq_self hs' (hnu j)]

f2ad3645

bump to nightly-2024-03-17-08

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

22f01ce4

Diff

@@ -92,7 +92,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
   suffices ∀ᶠ j in l, μ (s ∩ I j) / μ (I j) = μ s / ENNReal.ofReal T
     by
     replace hd := hd.congr' this
-    rwa [tendsto_const_nhds_iff, ENNReal.div_eq_one_iff hT₁ ENNReal.ofReal_ne_top] at hd 
+    rwa [tendsto_const_nhds_iff, ENNReal.div_eq_one_iff hT₁ ENNReal.ofReal_ne_top] at hd
   refine' (hu₂.eventually_gt_at_top 0).mono fun j hj => _
   have huj : IsOfFinAddOrder (u j) := add_order_of_pos_iff.mp hj
   have huj' : 1 ≤ (↑(n j) : ℝ) := by norm_cast; exact nat.succ_le_iff.mpr hj
@@ -116,7 +116,7 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
     ae_empty_or_univ := fun s hs hs' =>
       by
       let u : ℕ → AddCircle T := fun j => ↑((↑1 : ℝ) / ↑(n.nat_abs ^ j) * T)
-      replace hn : 1 < n.nat_abs; · rwa [Int.abs_eq_natAbs, Nat.one_lt_cast] at hn 
+      replace hn : 1 < n.nat_abs; · rwa [Int.abs_eq_natAbs, Nat.one_lt_cast] at hn
       have hu₀ : ∀ j, addOrderOf (u j) = n.nat_abs ^ j := fun j =>
         add_order_of_div_of_gcd_eq_one (pow_pos (pos_of_gt hn) j) (gcd_one_left _)
       have hnu : ∀ j, n ^ j • u j = 0 := fun j => by
@@ -145,7 +145,7 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
   suffices e ∘ f ∘ e.symm = fun y => n • y by rw [← he.ergodic_conjugate_iff, this];
     exact ergodic_zsmul h
   replace h : n - 1 ≠ 0;
-  · rw [← abs_one] at h ; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
+  · rw [← abs_one] at h; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
   have hnx : n • DivisibleBy.div x (n - 1) = x + DivisibleBy.div x (n - 1) := by
     conv_rhs =>
       congr

f2ad3645

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) 2022 Oliver Nash. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Oliver Nash
 -/
-import Mathbin.MeasureTheory.Group.AddCircle
-import Mathbin.Dynamics.Ergodic.Ergodic
-import Mathbin.MeasureTheory.Covering.DensityTheorem
-import Mathbin.Data.Set.Pointwise.Iterate
+import MeasureTheory.Group.AddCircle
+import Dynamics.Ergodic.Ergodic
+import MeasureTheory.Covering.DensityTheorem
+import Data.Set.Pointwise.Iterate
 
 #align_import dynamics.ergodic.add_circle from "leanprover-community/mathlib"@"f2ad3645af9effcdb587637dc28a6074edc813f9"

f2ad3645

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) 2022 Oliver Nash. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Oliver Nash
-
-! This file was ported from Lean 3 source module dynamics.ergodic.add_circle
-! leanprover-community/mathlib commit f2ad3645af9effcdb587637dc28a6074edc813f9
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.MeasureTheory.Group.AddCircle
 import Mathbin.Dynamics.Ergodic.Ergodic
 import Mathbin.MeasureTheory.Covering.DensityTheorem
 import Mathbin.Data.Set.Pointwise.Iterate
 
+#align_import dynamics.ergodic.add_circle from "leanprover-community/mathlib"@"f2ad3645af9effcdb587637dc28a6074edc813f9"
+
 /-!
 # Ergodic maps of the additive circle

f2ad3645

bump to nightly-2023-06-21-03

mathlib commit https://github.com/leanprover-community/mathlib/commit/f2ad3645af9effcdb587637dc28a6074edc813f9

78c41114

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Oliver Nash
 
 ! This file was ported from Lean 3 source module dynamics.ergodic.add_circle
-! leanprover-community/mathlib commit 5f6e827d81dfbeb6151d7016586ceeb0099b9655
+! leanprover-community/mathlib commit f2ad3645af9effcdb587637dc28a6074edc813f9
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -16,6 +16,9 @@ import Mathbin.Data.Set.Pointwise.Iterate
 /-!
 # Ergodic maps of the additive circle
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 This file contains proofs of ergodicity for maps of the additive circle.
 
 ## Main definitions:

5f6e827d

bump to nightly-2023-06-19-11

mathlib commit https://github.com/leanprover-community/mathlib/commit/2a0ce625dbb0ffbc7d1316597de0b25c1ec75303

d81759a2

Diff

@@ -40,6 +40,7 @@ namespace AddCircle
 
 variable {T : ℝ} [hT : Fact (0 < T)]
 
+#print AddCircle.ae_empty_or_univ_of_forall_vadd_ae_eq_self /-
 /-- If a null-measurable subset of the circle is almost invariant under rotation by a family of
 rational angles with denominators tending to infinity, then it must be almost empty or almost full.
 -/
@@ -107,7 +108,9 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     volume_of_add_preimage_eq s _ (u j) d huj (hu₁ j) closed_ball_ae_eq_ball, nsmul_eq_mul, ←
     mul_assoc, hI₂]
 #align add_circle.ae_empty_or_univ_of_forall_vadd_ae_eq_self AddCircle.ae_empty_or_univ_of_forall_vadd_ae_eq_self
+-/
 
+#print AddCircle.ergodic_zsmul /-
 theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T => n • y :=
   { measurePreserving_zsmul volume (abs_pos.mp <| lt_trans zero_lt_one hn) with
     ae_empty_or_univ := fun s hs hs' =>
@@ -125,11 +128,15 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
         exact Nat.tendsto_pow_atTop_atTop_of_one_lt hn
       exact ae_empty_or_univ_of_forall_vadd_ae_eq_self hs.null_measurable_set hu₁ hu₂ }
 #align add_circle.ergodic_zsmul AddCircle.ergodic_zsmul
+-/
 
+#print AddCircle.ergodic_nsmul /-
 theorem ergodic_nsmul {n : ℕ} (hn : 1 < n) : Ergodic fun y : AddCircle T => n • y :=
   ergodic_zsmul (by simp [hn] : 1 < |(n : ℤ)|)
 #align add_circle.ergodic_nsmul AddCircle.ergodic_nsmul
+-/
 
+#print AddCircle.ergodic_zsmul_add /-
 theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fun y => n • y + x :=
   by
   set f : AddCircle T → AddCircle T := fun y => n • y + x
@@ -149,10 +156,13 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
     zsmul_neg', neg_smul, neg_add_rev]
   abel
 #align add_circle.ergodic_zsmul_add AddCircle.ergodic_zsmul_add
+-/
 
+#print AddCircle.ergodic_nsmul_add /-
 theorem ergodic_nsmul_add (x : AddCircle T) {n : ℕ} (h : 1 < n) : Ergodic fun y => n • y + x :=
   ergodic_zsmul_add x (by simp [h] : 1 < |(n : ℤ)|)
 #align add_circle.ergodic_nsmul_add AddCircle.ergodic_nsmul_add
+-/
 
 end AddCircle

5f6e827d

bump to nightly-2023-06-13-21

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

829520ac

Diff

@@ -40,8 +40,6 @@ namespace AddCircle
 
 variable {T : ℝ} [hT : Fact (0 < T)]
 
-include hT
-
 /-- If a null-measurable subset of the circle is almost invariant under rotation by a family of
 rational angles with denominators tending to infinity, then it must be almost empty or almost full.
 -/

5f6e827d

bump to nightly-2023-06-01-16

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

b9c87c70

Diff

@@ -93,7 +93,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
   suffices ∀ᶠ j in l, μ (s ∩ I j) / μ (I j) = μ s / ENNReal.ofReal T
     by
     replace hd := hd.congr' this
-    rwa [tendsto_const_nhds_iff, ENNReal.div_eq_one_iff hT₁ ENNReal.ofReal_ne_top] at hd
+    rwa [tendsto_const_nhds_iff, ENNReal.div_eq_one_iff hT₁ ENNReal.ofReal_ne_top] at hd 
   refine' (hu₂.eventually_gt_at_top 0).mono fun j hj => _
   have huj : IsOfFinAddOrder (u j) := add_order_of_pos_iff.mp hj
   have huj' : 1 ≤ (↑(n j) : ℝ) := by norm_cast; exact nat.succ_le_iff.mpr hj
@@ -115,7 +115,7 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
     ae_empty_or_univ := fun s hs hs' =>
       by
       let u : ℕ → AddCircle T := fun j => ↑((↑1 : ℝ) / ↑(n.nat_abs ^ j) * T)
-      replace hn : 1 < n.nat_abs; · rwa [Int.abs_eq_natAbs, Nat.one_lt_cast] at hn
+      replace hn : 1 < n.nat_abs; · rwa [Int.abs_eq_natAbs, Nat.one_lt_cast] at hn 
       have hu₀ : ∀ j, addOrderOf (u j) = n.nat_abs ^ j := fun j =>
         add_order_of_div_of_gcd_eq_one (pow_pos (pos_of_gt hn) j) (gcd_one_left _)
       have hnu : ∀ j, n ^ j • u j = 0 := fun j => by
@@ -140,7 +140,7 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
   suffices e ∘ f ∘ e.symm = fun y => n • y by rw [← he.ergodic_conjugate_iff, this];
     exact ergodic_zsmul h
   replace h : n - 1 ≠ 0;
-  · rw [← abs_one] at h; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
+  · rw [← abs_one] at h ; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
   have hnx : n • DivisibleBy.div x (n - 1) = x + DivisibleBy.div x (n - 1) := by
     conv_rhs =>
       congr

5f6e827d

bump to nightly-2023-05-28-18

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

8d353152

Diff

@@ -34,7 +34,7 @@ This file contains proofs of ergodicity for maps of the additive circle.
 
 open Set Function MeasureTheory MeasureTheory.Measure Filter Metric
 
-open MeasureTheory NNReal ENNReal Topology Pointwise
+open scoped MeasureTheory NNReal ENNReal Topology Pointwise
 
 namespace AddCircle

5f6e827d

bump to nightly-2023-05-28-04

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

6797a637

Diff

@@ -63,8 +63,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
   have hT₀ : 0 < T := hT.out
   have hT₁ : ENNReal.ofReal T ≠ 0 := by simpa
   rw [ae_eq_empty, ae_eq_univ_iff_measure_eq hs, AddCircle.measure_univ]
-  cases' eq_or_ne (μ s) 0 with h h
-  · exact Or.inl h
+  cases' eq_or_ne (μ s) 0 with h h; · exact Or.inl h
   right
   obtain ⟨d, -, hd⟩ :
     ∃ d,
@@ -97,9 +96,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     rwa [tendsto_const_nhds_iff, ENNReal.div_eq_one_iff hT₁ ENNReal.ofReal_ne_top] at hd
   refine' (hu₂.eventually_gt_at_top 0).mono fun j hj => _
   have huj : IsOfFinAddOrder (u j) := add_order_of_pos_iff.mp hj
-  have huj' : 1 ≤ (↑(n j) : ℝ) := by
-    norm_cast
-    exact nat.succ_le_iff.mpr hj
+  have huj' : 1 ≤ (↑(n j) : ℝ) := by norm_cast; exact nat.succ_le_iff.mpr hj
   have hI₀ : μ (I j) ≠ 0 := (measure_closed_ball_pos _ d <| by positivity).Ne.symm
   have hI₁ : μ (I j) ≠ ⊤ := measure_ne_top _ _
   have hI₂ : μ (I j) * ↑(n j) = ENNReal.ofReal T :=
@@ -118,8 +115,7 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
     ae_empty_or_univ := fun s hs hs' =>
       by
       let u : ℕ → AddCircle T := fun j => ↑((↑1 : ℝ) / ↑(n.nat_abs ^ j) * T)
-      replace hn : 1 < n.nat_abs
-      · rwa [Int.abs_eq_natAbs, Nat.one_lt_cast] at hn
+      replace hn : 1 < n.nat_abs; · rwa [Int.abs_eq_natAbs, Nat.one_lt_cast] at hn
       have hu₀ : ∀ j, addOrderOf (u j) = n.nat_abs ^ j := fun j =>
         add_order_of_div_of_gcd_eq_one (pow_pos (pos_of_gt hn) j) (gcd_one_left _)
       have hnu : ∀ j, n ^ j • u j = 0 := fun j => by
@@ -127,9 +123,7 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
           abs_dvd]
       have hu₁ : ∀ j, (u j +ᵥ s : Set _) =ᵐ[volume] s := fun j => by
         rw [vadd_eq_self_of_preimage_zsmul_eq_self hs' (hnu j)]
-      have hu₂ : tendsto (fun j => addOrderOf <| u j) at_top at_top :=
-        by
-        simp_rw [hu₀]
+      have hu₂ : tendsto (fun j => addOrderOf <| u j) at_top at_top := by simp_rw [hu₀];
         exact Nat.tendsto_pow_atTop_atTop_of_one_lt hn
       exact ae_empty_or_univ_of_forall_vadd_ae_eq_self hs.null_measurable_set hu₁ hu₂ }
 #align add_circle.ergodic_zsmul AddCircle.ergodic_zsmul
@@ -143,19 +137,14 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
   set f : AddCircle T → AddCircle T := fun y => n • y + x
   let e : AddCircle T ≃ᵐ AddCircle T := MeasurableEquiv.addLeft (DivisibleBy.div x <| n - 1)
   have he : measure_preserving e volume volume := measure_preserving_add_left volume _
-  suffices e ∘ f ∘ e.symm = fun y => n • y
-    by
-    rw [← he.ergodic_conjugate_iff, this]
+  suffices e ∘ f ∘ e.symm = fun y => n • y by rw [← he.ergodic_conjugate_iff, this];
     exact ergodic_zsmul h
-  replace h : n - 1 ≠ 0
-  · rw [← abs_one] at h
-    rw [sub_ne_zero]
-    exact ne_of_apply_ne _ (ne_of_gt h)
-  have hnx : n • DivisibleBy.div x (n - 1) = x + DivisibleBy.div x (n - 1) :=
-    by
+  replace h : n - 1 ≠ 0;
+  · rw [← abs_one] at h; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
+  have hnx : n • DivisibleBy.div x (n - 1) = x + DivisibleBy.div x (n - 1) := by
     conv_rhs =>
       congr
-      rw [← DivisibleBy.div_cancel x h]
+      rw [← DivisibleBy.div_cancel x h];
     rw [sub_smul, one_smul, sub_add_cancel]
   ext y
   simp only [f, hnx, MeasurableEquiv.coe_addLeft, MeasurableEquiv.symm_addLeft, comp_app, smul_add,

5f6e827d

bump to nightly-2023-05-11-08

mathlib commit https://github.com/leanprover-community/mathlib/commit/28b2a92f2996d28e580450863c130955de0ed398

66e23fb2

Diff

@@ -158,8 +158,8 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
       rw [← DivisibleBy.div_cancel x h]
     rw [sub_smul, one_smul, sub_add_cancel]
   ext y
-  simp only [f, hnx, MeasurableEquiv.coe_add_left, MeasurableEquiv.symm_add_left, comp_app,
-    smul_add, zsmul_neg', neg_smul, neg_add_rev]
+  simp only [f, hnx, MeasurableEquiv.coe_addLeft, MeasurableEquiv.symm_addLeft, comp_app, smul_add,
+    zsmul_neg', neg_smul, neg_add_rev]
   abel
 #align add_circle.ergodic_zsmul_add AddCircle.ergodic_zsmul_add

5f6e827d

bump to nightly-2023-05-04-10

mathlib commit https://github.com/leanprover-community/mathlib/commit/92c69b77c5a7dc0f7eeddb552508633305157caa

3d8894bd

Diff

@@ -113,8 +113,8 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     mul_assoc, hI₂]
 #align add_circle.ae_empty_or_univ_of_forall_vadd_ae_eq_self AddCircle.ae_empty_or_univ_of_forall_vadd_ae_eq_self
 
-theorem ergodicZsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T => n • y :=
-  { measure_preserving_zsmul volume (abs_pos.mp <| lt_trans zero_lt_one hn) with
+theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T => n • y :=
+  { measurePreserving_zsmul volume (abs_pos.mp <| lt_trans zero_lt_one hn) with
     ae_empty_or_univ := fun s hs hs' =>
       by
       let u : ℕ → AddCircle T := fun j => ↑((↑1 : ℝ) / ↑(n.nat_abs ^ j) * T)
@@ -132,13 +132,13 @@ theorem ergodicZsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T => n
         simp_rw [hu₀]
         exact Nat.tendsto_pow_atTop_atTop_of_one_lt hn
       exact ae_empty_or_univ_of_forall_vadd_ae_eq_self hs.null_measurable_set hu₁ hu₂ }
-#align add_circle.ergodic_zsmul AddCircle.ergodicZsmul
+#align add_circle.ergodic_zsmul AddCircle.ergodic_zsmul
 
-theorem ergodicNsmul {n : ℕ} (hn : 1 < n) : Ergodic fun y : AddCircle T => n • y :=
-  ergodicZsmul (by simp [hn] : 1 < |(n : ℤ)|)
-#align add_circle.ergodic_nsmul AddCircle.ergodicNsmul
+theorem ergodic_nsmul {n : ℕ} (hn : 1 < n) : Ergodic fun y : AddCircle T => n • y :=
+  ergodic_zsmul (by simp [hn] : 1 < |(n : ℤ)|)
+#align add_circle.ergodic_nsmul AddCircle.ergodic_nsmul
 
-theorem ergodicZsmulAdd (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fun y => n • y + x :=
+theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fun y => n • y + x :=
   by
   set f : AddCircle T → AddCircle T := fun y => n • y + x
   let e : AddCircle T ≃ᵐ AddCircle T := MeasurableEquiv.addLeft (DivisibleBy.div x <| n - 1)
@@ -161,11 +161,11 @@ theorem ergodicZsmulAdd (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fun
   simp only [f, hnx, MeasurableEquiv.coe_add_left, MeasurableEquiv.symm_add_left, comp_app,
     smul_add, zsmul_neg', neg_smul, neg_add_rev]
   abel
-#align add_circle.ergodic_zsmul_add AddCircle.ergodicZsmulAdd
+#align add_circle.ergodic_zsmul_add AddCircle.ergodic_zsmul_add
 
-theorem ergodicNsmulAdd (x : AddCircle T) {n : ℕ} (h : 1 < n) : Ergodic fun y => n • y + x :=
-  ergodicZsmulAdd x (by simp [h] : 1 < |(n : ℤ)|)
-#align add_circle.ergodic_nsmul_add AddCircle.ergodicNsmulAdd
+theorem ergodic_nsmul_add (x : AddCircle T) {n : ℕ} (h : 1 < n) : Ergodic fun y => n • y + x :=
+  ergodic_zsmul_add x (by simp [h] : 1 < |(n : ℤ)|)
+#align add_circle.ergodic_nsmul_add AddCircle.ergodic_nsmul_add
 
 end AddCircle

5f6e827d

bump to nightly-2023-04-03-02

mathlib commit https://github.com/leanprover-community/mathlib/commit/d95bef0d215ea58c0fd7bbc4b151bf3fe952c095

8477bcac

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Oliver Nash
 
 ! This file was ported from Lean 3 source module dynamics.ergodic.add_circle
-! leanprover-community/mathlib commit f2ce6086713c78a7f880485f7917ea547a215982
+! leanprover-community/mathlib commit 5f6e827d81dfbeb6151d7016586ceeb0099b9655
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -74,7 +74,8 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
             (∀ᶠ j in l, d ∈ closed_ball (w j) (1 * δ j)) →
               tendsto (fun j => μ (s ∩ closed_ball (w j) (δ j)) / μ (closed_ball (w j) (δ j))) l
                 (𝓝 1) :=
-    exists_mem_of_measure_ne_zero_of_ae h (IsDoublingMeasure.ae_tendsto_measure_inter_div μ s 1)
+    exists_mem_of_measure_ne_zero_of_ae h
+      (IsUnifLocDoublingMeasure.ae_tendsto_measure_inter_div μ s 1)
   let I : ι → Set (AddCircle T) := fun j => closed_ball d (T / (2 * ↑(n j)))
   replace hd : tendsto (fun j => μ (s ∩ I j) / μ (I j)) l (𝓝 1)
   · let δ : ι → ℝ := fun j => T / (2 * ↑(n j))

f2ce6086

bump to nightly-2023-02-27-10

mathlib commit https://github.com/leanprover-community/mathlib/commit/eb0cb4511aaef0da2462207b67358a0e1fe1e2ee

49ff026a

Diff

@@ -34,7 +34,7 @@ This file contains proofs of ergodicity for maps of the additive circle.
 
 open Set Function MeasureTheory MeasureTheory.Measure Filter Metric
 
-open MeasureTheory NNReal Ennreal Topology Pointwise
+open MeasureTheory NNReal ENNReal Topology Pointwise
 
 namespace AddCircle
 
@@ -61,7 +61,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
   set μ := (volume : Measure <| AddCircle T)
   set n : ι → ℕ := addOrderOf ∘ u
   have hT₀ : 0 < T := hT.out
-  have hT₁ : Ennreal.ofReal T ≠ 0 := by simpa
+  have hT₁ : ENNReal.ofReal T ≠ 0 := by simpa
   rw [ae_eq_empty, ae_eq_univ_iff_measure_eq hs, AddCircle.measure_univ]
   cases' eq_or_ne (μ s) 0 with h h
   · exact Or.inl h
@@ -90,10 +90,10 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
       simp only [δ, Pi.inv_apply, mul_inv_rev, inv_inv, div_eq_inv_mul, ← mul_assoc]
     have hw : ∀ᶠ j in l, d ∈ closed_ball d (1 * δ j) := hδ₀.mono fun j hj => by simp [hj.le]
     exact hd _ δ hδ₁ hw
-  suffices ∀ᶠ j in l, μ (s ∩ I j) / μ (I j) = μ s / Ennreal.ofReal T
+  suffices ∀ᶠ j in l, μ (s ∩ I j) / μ (I j) = μ s / ENNReal.ofReal T
     by
     replace hd := hd.congr' this
-    rwa [tendsto_const_nhds_iff, Ennreal.div_eq_one_iff hT₁ Ennreal.ofReal_ne_top] at hd
+    rwa [tendsto_const_nhds_iff, ENNReal.div_eq_one_iff hT₁ ENNReal.ofReal_ne_top] at hd
   refine' (hu₂.eventually_gt_at_top 0).mono fun j hj => _
   have huj : IsOfFinAddOrder (u j) := add_order_of_pos_iff.mp hj
   have huj' : 1 ≤ (↑(n j) : ℝ) := by
@@ -101,13 +101,13 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     exact nat.succ_le_iff.mpr hj
   have hI₀ : μ (I j) ≠ 0 := (measure_closed_ball_pos _ d <| by positivity).Ne.symm
   have hI₁ : μ (I j) ≠ ⊤ := measure_ne_top _ _
-  have hI₂ : μ (I j) * ↑(n j) = Ennreal.ofReal T :=
+  have hI₂ : μ (I j) * ↑(n j) = ENNReal.ofReal T :=
     by
     rw [volume_closed_ball, mul_div, mul_div_mul_left T _ two_ne_zero,
-      min_eq_right (div_le_self hT₀.le huj'), mul_comm, ← nsmul_eq_mul, ← Ennreal.ofReal_nsmul,
+      min_eq_right (div_le_self hT₀.le huj'), mul_comm, ← nsmul_eq_mul, ← ENNReal.ofReal_nsmul,
       nsmul_eq_mul, mul_div_cancel']
     exact nat.cast_ne_zero.mpr hj.ne'
-  rw [Ennreal.div_eq_div_iff hT₁ Ennreal.ofReal_ne_top hI₀ hI₁,
+  rw [ENNReal.div_eq_div_iff hT₁ ENNReal.ofReal_ne_top hI₀ hI₁,
     volume_of_add_preimage_eq s _ (u j) d huj (hu₁ j) closed_ball_ae_eq_ball, nsmul_eq_mul, ←
     mul_assoc, hI₂]
 #align add_circle.ae_empty_or_univ_of_forall_vadd_ae_eq_self AddCircle.ae_empty_or_univ_of_forall_vadd_ae_eq_self

f2ce6086

bump to nightly-2023-02-22-21

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

0652cf4a

Diff

@@ -122,7 +122,7 @@ theorem ergodicZsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T => n
       have hu₀ : ∀ j, addOrderOf (u j) = n.nat_abs ^ j := fun j =>
         add_order_of_div_of_gcd_eq_one (pow_pos (pos_of_gt hn) j) (gcd_one_left _)
       have hnu : ∀ j, n ^ j • u j = 0 := fun j => by
-        rw [← add_orderOf_dvd_iff_zsmul_eq_zero, hu₀, Int.coe_nat_pow, Int.coe_natAbs, ← abs_pow,
+        rw [← addOrderOf_dvd_iff_zsmul_eq_zero, hu₀, Int.coe_nat_pow, Int.coe_natAbs, ← abs_pow,
           abs_dvd]
       have hu₁ : ∀ j, (u j +ᵥ s : Set _) =ᵐ[volume] s := fun j => by
         rw [vadd_eq_self_of_preimage_zsmul_eq_self hs' (hnu j)]

f2ce6086

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

5f6e827d

chore: Rename nat_cast/int_cast/rat_cast to natCast/intCast/ratCast (#11486)

Now that I am defining NNRat.cast, I want a definitive answer to this naming issue. Plenty of lemmas in mathlib already use natCast/intCast/ratCast over nat_cast/int_cast/rat_cast, and this matches with the general expectation that underscore-separated name parts correspond to a single declaration.

145460b9

Diff

@@ -74,7 +74,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     have hδ₁ : Tendsto δ l (𝓝[>] 0) := by
       refine' tendsto_nhdsWithin_iff.mpr ⟨_, hδ₀⟩
       replace hu₂ : Tendsto (fun j => T⁻¹ * 2 * n j) l atTop :=
-        (tendsto_nat_cast_atTop_iff.mpr hu₂).const_mul_atTop (by positivity : 0 < T⁻¹ * 2)
+        (tendsto_natCast_atTop_iff.mpr hu₂).const_mul_atTop (by positivity : 0 < T⁻¹ * 2)
       convert hu₂.inv_tendsto_atTop
       ext j
       simp only [δ, Pi.inv_apply, mul_inv_rev, inv_inv, div_eq_inv_mul, ← mul_assoc]

5f6e827d

chore(Data/Int): Rename coe_nat to natCast (#11637)

Reduce the diff of #11499

Renames

All in the Int namespace:

ofNat_eq_cast → ofNat_eq_natCast
cast_eq_cast_iff_Nat → natCast_inj
natCast_eq_ofNat → ofNat_eq_natCast
coe_nat_sub → natCast_sub
coe_nat_nonneg → natCast_nonneg
sign_coe_add_one → sign_natCast_add_one
nat_succ_eq_int_succ → natCast_succ
succ_neg_nat_succ → succ_neg_natCast_succ
coe_pred_of_pos → natCast_pred_of_pos
coe_nat_div → natCast_div
coe_nat_ediv → natCast_ediv
sign_coe_nat_of_nonzero → sign_natCast_of_ne_zero
toNat_coe_nat → toNat_natCast
toNat_coe_nat_add_one → toNat_natCast_add_one
coe_nat_dvd → natCast_dvd_natCast
coe_nat_dvd_left → natCast_dvd
coe_nat_dvd_right → dvd_natCast
le_coe_nat_sub → le_natCast_sub
succ_coe_nat_pos → succ_natCast_pos
coe_nat_modEq_iff → natCast_modEq_iff
coe_natAbs → natCast_natAbs
coe_nat_eq_zero → natCast_eq_zero
coe_nat_ne_zero → natCast_ne_zero
coe_nat_ne_zero_iff_pos → natCast_ne_zero_iff_pos
abs_coe_nat → abs_natCast
coe_nat_nonpos_iff → natCast_nonpos_iff

Also rename Nat.coe_nat_dvd to Nat.cast_dvd_cast

392a24a9

Diff

@@ -111,7 +111,7 @@ theorem ergodic_zsmul {n : ℤ} (hn : 1 < |n|) : Ergodic fun y : AddCircle T =>
           (pow_pos (pos_of_gt hn) j) (gcd_one_left _)
         norm_cast
       have hnu : ∀ j, n ^ j • u j = 0 := fun j => by
-        rw [← addOrderOf_dvd_iff_zsmul_eq_zero, hu₀, Int.coe_nat_pow, Int.coe_natAbs, ← abs_pow,
+        rw [← addOrderOf_dvd_iff_zsmul_eq_zero, hu₀, Int.coe_nat_pow, Int.natCast_natAbs, ← abs_pow,
           abs_dvd]
       have hu₁ : ∀ j, (u j +ᵥ s : Set _) =ᵐ[volume] s := fun j => by
         rw [vadd_eq_self_of_preimage_zsmul_eq_self hs' (hnu j)]

5f6e827d

chore: Rename mul-div cancellation lemmas (#11530)

Lemma names around cancellation of multiplication and division are a mess.

This PR renames a handful of them according to the following table (each big row contains the multiplicative statement, then the three rows contain the GroupWithZero lemma name, the Group lemma, the AddGroup lemma name).

4ea4a86a

Diff

@@ -94,7 +94,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
   have hI₂ : μ (I j) * ↑(n j) = ENNReal.ofReal T := by
     rw [volume_closedBall, mul_div, mul_div_mul_left T _ two_ne_zero,
       min_eq_right (div_le_self hT₀.le huj'), mul_comm, ← nsmul_eq_mul, ← ENNReal.ofReal_nsmul,
-      nsmul_eq_mul, mul_div_cancel']
+      nsmul_eq_mul, mul_div_cancel₀]
     exact Nat.cast_ne_zero.mpr hj.ne'
   rw [ENNReal.div_eq_div_iff hT₁ ENNReal.ofReal_ne_top hI₀ hI₁,
     volume_of_add_preimage_eq s _ (u j) d huj (hu₁ j) closedBall_ae_eq_ball, nsmul_eq_mul, ←

5f6e827d

chore: prepare Lean version bump with explicit simp (#10999)

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

38bce757

Diff

@@ -77,7 +77,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
         (tendsto_nat_cast_atTop_iff.mpr hu₂).const_mul_atTop (by positivity : 0 < T⁻¹ * 2)
       convert hu₂.inv_tendsto_atTop
       ext j
-      simp only [Pi.inv_apply, mul_inv_rev, inv_inv, div_eq_inv_mul, ← mul_assoc]
+      simp only [δ, Pi.inv_apply, mul_inv_rev, inv_inv, div_eq_inv_mul, ← mul_assoc]
     have hw : ∀ᶠ j in l, d ∈ closedBall d (1 * δ j) := hδ₀.mono fun j hj => by
       simp only [comp_apply, one_mul, mem_closedBall, dist_self]
       apply hj.le
@@ -137,8 +137,8 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
     conv_rhs => congr; rw [← DivisibleBy.div_cancel x h]
     rw [sub_smul, one_smul, sub_add_cancel]
   ext y
-  simp only [hnx, MeasurableEquiv.coe_addLeft, MeasurableEquiv.symm_addLeft, comp_apply, smul_add,
-    zsmul_neg', neg_smul, neg_add_rev]
+  simp only [f, e, hnx, MeasurableEquiv.coe_addLeft, MeasurableEquiv.symm_addLeft, comp_apply,
+    smul_add, zsmul_neg', neg_smul, neg_add_rev]
   abel
 #align add_circle.ergodic_zsmul_add AddCircle.ergodic_zsmul_add

5f6e827d

chore: remove stream-of-consciousness uses of have, replace and suffices (#10640)

No changes to tactic file, it's just boring fixes throughout the library.

This follows on from #6964.

Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Eric Wieser <wieser.eric@gmail.com>

a13e8040

Diff

@@ -67,8 +67,8 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
     exists_mem_of_measure_ne_zero_of_ae h
       (IsUnifLocDoublingMeasure.ae_tendsto_measure_inter_div μ s 1)
   let I : ι → Set (AddCircle T) := fun j => closedBall d (T / (2 * ↑(n j)))
-  replace hd : Tendsto (fun j => μ (s ∩ I j) / μ (I j)) l (𝓝 1)
-  · let δ : ι → ℝ := fun j => T / (2 * ↑(n j))
+  replace hd : Tendsto (fun j => μ (s ∩ I j) / μ (I j)) l (𝓝 1) := by
+    let δ : ι → ℝ := fun j => T / (2 * ↑(n j))
     have hδ₀ : ∀ᶠ j in l, 0 < δ j :=
       (hu₂.eventually_gt_atTop 0).mono fun j hj => div_pos hT₀ <| by positivity
     have hδ₁ : Tendsto δ l (𝓝[>] 0) := by
@@ -131,8 +131,8 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
     measurePreserving_add_left volume (DivisibleBy.div x <| n - 1)
   suffices e ∘ f ∘ e.symm = fun y => n • y by
     rw [← he.ergodic_conjugate_iff, this]; exact ergodic_zsmul h
-  replace h : n - 1 ≠ 0
-  · rw [← abs_one] at h; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
+  replace h : n - 1 ≠ 0 := by
+    rw [← abs_one] at h; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
   have hnx : n • DivisibleBy.div x (n - 1) = x + DivisibleBy.div x (n - 1) := by
     conv_rhs => congr; rw [← DivisibleBy.div_cancel x h]
     rw [sub_smul, one_smul, sub_add_cancel]

5f6e827d

refactor: Delete Algebra.GroupPower.Lemmas (#9411)

Algebra.GroupPower.Lemmas used to be a big bag of lemmas that made it there on the criterion that they needed "more imports". This was completely untrue, as all lemmas could be moved to earlier files in PRs:

There are several reasons for this:

Necessary lemmas have been moved to earlier files since lemmas were dumped in Algebra.GroupPower.Lemmas
In the Lean 3 → Lean 4 transition, Std acquired basic Int and Nat lemmas which let us shortcircuit the part of the algebraic order hierarchy on which the corresponding general lemmas rest
Some proofs were overpowered
Some earlier files were tangled and I have untangled them

This PR finishes the job by moving the last few lemmas out of Algebra.GroupPower.Lemmas, which is therefore deleted.

6eb43dc3

Diff

@@ -3,10 +3,11 @@ Copyright (c) 2022 Oliver Nash. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Oliver Nash
 -/
-import Mathlib.MeasureTheory.Group.AddCircle
+import Mathlib.Algebra.Order.Ring.Abs
+import Mathlib.Data.Set.Pointwise.Iterate
 import Mathlib.Dynamics.Ergodic.Ergodic
 import Mathlib.MeasureTheory.Covering.DensityTheorem
-import Mathlib.Data.Set.Pointwise.Iterate
+import Mathlib.MeasureTheory.Group.AddCircle
 import Mathlib.MeasureTheory.Measure.Haar.Unique
 
 #align_import dynamics.ergodic.add_circle from "leanprover-community/mathlib"@"5f6e827d81dfbeb6151d7016586ceeb0099b9655"

5f6e827d

chore: remove uses of cases' (#9171)

I literally went through and regex'd some uses of cases', replacing them with rcases; this is meant to be a low effort PR as I hope that tools can do this in the future.

rcases is an easier replacement than cases, though with better tools we could in future do a second pass converting simple rcases added here (and existing ones) to cases.

3fca282c

Diff

@@ -58,7 +58,7 @@ theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
   have hT₀ : 0 < T := hT.out
   have hT₁ : ENNReal.ofReal T ≠ 0 := by simpa
   rw [ae_eq_empty, ae_eq_univ_iff_measure_eq hs, AddCircle.measure_univ]
-  cases' eq_or_ne (μ s) 0 with h h; · exact Or.inl h
+  rcases eq_or_ne (μ s) 0 with h | h; · exact Or.inl h
   right
   obtain ⟨d, -, hd⟩ : ∃ d, d ∈ s ∧ ∀ {ι'} {l : Filter ι'} (w : ι' → AddCircle T) (δ : ι' → ℝ),
     Tendsto δ l (𝓝[>] 0) → (∀ᶠ j in l, d ∈ closedBall (w j) (1 * δ j)) →

5f6e827d

feat: uniqueness of Haar measure in general locally compact groups (#8198)

We prove that two regular Haar measures in a locally compact group coincide up to scalar multiplication, and the same thing for inner regular Haar measures. This is implemented in a new file MeasureTheory.Measure.Haar.Unique. A few results that used to be in the MeasureTheory.Measure.Haar.Basic are moved to this file (and extended) so several imports have to be changed.

722e62ad

Diff

@@ -7,6 +7,7 @@ import Mathlib.MeasureTheory.Group.AddCircle
 import Mathlib.Dynamics.Ergodic.Ergodic
 import Mathlib.MeasureTheory.Covering.DensityTheorem
 import Mathlib.Data.Set.Pointwise.Iterate
+import Mathlib.MeasureTheory.Measure.Haar.Unique
 
 #align_import dynamics.ergodic.add_circle from "leanprover-community/mathlib"@"5f6e827d81dfbeb6151d7016586ceeb0099b9655"

5f6e827d

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

@@ -41,7 +41,7 @@ variable {T : ℝ} [hT : Fact (0 < T)]
 rational angles with denominators tending to infinity, then it must be almost empty or almost full.
 -/
 theorem ae_empty_or_univ_of_forall_vadd_ae_eq_self {s : Set <| AddCircle T}
-    (hs : NullMeasurableSet s volume) {ι : Type _} {l : Filter ι} [l.NeBot] {u : ι → AddCircle T}
+    (hs : NullMeasurableSet s volume) {ι : Type*} {l : Filter ι} [l.NeBot] {u : ι → AddCircle T}
     (hu₁ : ∀ i, (u i +ᵥ s : Set _) =ᵐ[volume] s) (hu₂ : Tendsto (addOrderOf ∘ u) l atTop) :
     s =ᵐ[volume] (∅ : Set <| AddCircle T) ∨ s =ᵐ[volume] univ := by
   /- Sketch of proof:

5f6e827d

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) 2022 Oliver Nash. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Oliver Nash
-
-! This file was ported from Lean 3 source module dynamics.ergodic.add_circle
-! leanprover-community/mathlib commit 5f6e827d81dfbeb6151d7016586ceeb0099b9655
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.MeasureTheory.Group.AddCircle
 import Mathlib.Dynamics.Ergodic.Ergodic
 import Mathlib.MeasureTheory.Covering.DensityTheorem
 import Mathlib.Data.Set.Pointwise.Iterate
 
+#align_import dynamics.ergodic.add_circle from "leanprover-community/mathlib"@"5f6e827d81dfbeb6151d7016586ceeb0099b9655"
+
 /-!
 # Ergodic maps of the additive circle

5f6e827d

chore: remove occurrences of semicolon after space (#5713)

This is the second half of the changes originally in #5699, removing all occurrences of ; after a space and implementing a linter rule to enforce it.

In most cases this 2-character substring has a space after it, so the following command was run first:

find . -type f -name "*.lean" -exec sed -i -E 's/ ; /; /g' {} \;

The remaining cases were few enough in number that they were done manually.

c795bd35

Diff

@@ -133,7 +133,7 @@ theorem ergodic_zsmul_add (x : AddCircle T) {n : ℤ} (h : 1 < |n|) : Ergodic fu
   suffices e ∘ f ∘ e.symm = fun y => n • y by
     rw [← he.ergodic_conjugate_iff, this]; exact ergodic_zsmul h
   replace h : n - 1 ≠ 0
-  · rw [← abs_one] at h ; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
+  · rw [← abs_one] at h; rw [sub_ne_zero]; exact ne_of_apply_ne _ (ne_of_gt h)
   have hnx : n • DivisibleBy.div x (n - 1) = x + DivisibleBy.div x (n - 1) := by
     conv_rhs => congr; rw [← DivisibleBy.div_cancel x h]
     rw [sub_smul, one_smul, sub_add_cancel]

5f6e827d

feat: port Dynamics.Ergodic.AddCircle (#5251)

89822627

`dynamics.ergodic.add_circle` ⟷ `Mathlib.Dynamics.Ergodic.AddCircle`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Renames

Dependencies 12 + 1038

dynamics.ergodic.add_circle ⟷ Mathlib.Dynamics.Ergodic.AddCircle

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Renames

Dependencies 12 + 1038

`dynamics.ergodic.add_circle` ⟷ `Mathlib.Dynamics.Ergodic.AddCircle`