combinatorics.additive.energy | 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

509de852

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

327c3c0d

bump to nightly-2024-03-17-08

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

22f01ce4

Diff

@@ -129,7 +129,7 @@ variable {s t}
 theorem multiplicativeEnergy_pos_iff : 0 < multiplicativeEnergy s t ↔ s.Nonempty ∧ t.Nonempty :=
   ⟨fun h =>
     of_not_not fun H => by
-      simp_rw [not_and_or, not_nonempty_iff_eq_empty] at H 
+      simp_rw [not_and_or, not_nonempty_iff_eq_empty] at H
       obtain rfl | rfl := H <;> simpa [Nat.not_lt_zero] using h,
     fun h => multiplicativeEnergy_pos h.1 h.2⟩
 #align finset.multiplicative_energy_pos_iff Finset.multiplicativeEnergy_pos_iff
@@ -179,7 +179,7 @@ theorem multiplicativeEnergy_univ_left :
   have : (↑((univ : Finset α) ×ˢ t ×ˢ t) : Set (α × α × α)).InjOn f :=
     by
     rintro ⟨a₁, b₁, c₁⟩ h₁ ⟨a₂, b₂, c₂⟩ h₂ h
-    simp_rw [Prod.ext_iff] at h 
+    simp_rw [Prod.ext_iff] at h
     obtain ⟨h, rfl, rfl⟩ := h
     rw [mul_right_cancel h.1]
   rw [← card_image_of_inj_on this]

327c3c0d

bump to nightly-2023-12-28-06

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

c30f5587

Diff

@@ -57,7 +57,7 @@ def multiplicativeEnergy (s t : Finset α) : ℕ :=
 @[to_additive additive_energy_mono]
 theorem multiplicativeEnergy_mono (hs : s₁ ⊆ s₂) (ht : t₁ ⊆ t₂) :
     multiplicativeEnergy s₁ t₁ ≤ multiplicativeEnergy s₂ t₂ :=
-  card_le_of_subset <|
+  card_le_card <|
     filter_subset_filter _ <|
       product_subset_product (product_subset_product hs hs) <| product_subset_product ht ht
 #align finset.multiplicative_energy_mono Finset.multiplicativeEnergy_mono

327c3c0d

bump to nightly-2023-09-24-06

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

5655435f

Diff

@@ -3,8 +3,8 @@ Copyright (c) 2022 Yaël Dillies, Ella Yu. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yaël Dillies, Ella Yu
 -/
-import Mathbin.Data.Finset.Prod
-import Mathbin.Data.Fintype.Prod
+import Data.Finset.Prod
+import Data.Fintype.Prod
 
 #align_import combinatorics.additive.energy from "leanprover-community/mathlib"@"327c3c0d9232d80e250dc8f65e7835b82b266ea5"

327c3c0d

bump to nightly-2023-07-20-09

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

9c56d0dd

Diff

@@ -2,15 +2,12 @@
 Copyright (c) 2022 Yaël Dillies, Ella Yu. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yaël Dillies, Ella Yu
-
-! This file was ported from Lean 3 source module combinatorics.additive.energy
-! leanprover-community/mathlib commit 327c3c0d9232d80e250dc8f65e7835b82b266ea5
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Data.Finset.Prod
 import Mathbin.Data.Fintype.Prod
 
+#align_import combinatorics.additive.energy from "leanprover-community/mathlib"@"327c3c0d9232d80e250dc8f65e7835b82b266ea5"
+
 /-!
 # Additive energy

327c3c0d

bump to nightly-2023-06-13-21

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

829520ac

Diff

@@ -153,6 +153,7 @@ section CommMonoid
 
 variable [CommMonoid α]
 
+#print Finset.multiplicativeEnergy_comm /-
 @[to_additive additive_energy_comm]
 theorem multiplicativeEnergy_comm (s t : Finset α) :
     multiplicativeEnergy s t = multiplicativeEnergy t s :=
@@ -161,6 +162,7 @@ theorem multiplicativeEnergy_comm (s t : Finset α) :
   simp [-Finset.card_map, eq_comm, multiplicative_energy, mul_comm, map_eq_image, Function.comp]
 #align finset.multiplicative_energy_comm Finset.multiplicativeEnergy_comm
 #align finset.additive_energy_comm Finset.additiveEnergy_comm
+-/
 
 end CommMonoid
 
@@ -170,6 +172,7 @@ variable [CommGroup α] [Fintype α] (s t : Finset α)
 
 /- ./././Mathport/Syntax/Translate/Expr.lean:177:8: unsupported: ambiguous notation -/
 /- ./././Mathport/Syntax/Translate/Expr.lean:177:8: unsupported: ambiguous notation -/
+#print Finset.multiplicativeEnergy_univ_left /-
 @[simp, to_additive additive_energy_univ_left]
 theorem multiplicativeEnergy_univ_left :
     multiplicativeEnergy univ t = Fintype.card α * t.card ^ 2 :=
@@ -191,13 +194,16 @@ theorem multiplicativeEnergy_univ_left :
   simpa [mul_right_comm]
 #align finset.multiplicative_energy_univ_left Finset.multiplicativeEnergy_univ_left
 #align finset.additive_energy_univ_left Finset.additiveEnergy_univ_left
+-/
 
+#print Finset.multiplicativeEnergy_univ_right /-
 @[simp, to_additive additive_energy_univ_right]
 theorem multiplicativeEnergy_univ_right :
     multiplicativeEnergy s univ = Fintype.card α * s.card ^ 2 := by
   rw [multiplicative_energy_comm, multiplicative_energy_univ_left]
 #align finset.multiplicative_energy_univ_right Finset.multiplicativeEnergy_univ_right
 #align finset.additive_energy_univ_right Finset.additiveEnergy_univ_right
+-/
 
 end CommGroup

327c3c0d

bump to nightly-2023-06-01-16

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

b9c87c70

Diff

@@ -132,7 +132,7 @@ variable {s t}
 theorem multiplicativeEnergy_pos_iff : 0 < multiplicativeEnergy s t ↔ s.Nonempty ∧ t.Nonempty :=
   ⟨fun h =>
     of_not_not fun H => by
-      simp_rw [not_and_or, not_nonempty_iff_eq_empty] at H
+      simp_rw [not_and_or, not_nonempty_iff_eq_empty] at H 
       obtain rfl | rfl := H <;> simpa [Nat.not_lt_zero] using h,
     fun h => multiplicativeEnergy_pos h.1 h.2⟩
 #align finset.multiplicative_energy_pos_iff Finset.multiplicativeEnergy_pos_iff
@@ -179,7 +179,7 @@ theorem multiplicativeEnergy_univ_left :
   have : (↑((univ : Finset α) ×ˢ t ×ˢ t) : Set (α × α × α)).InjOn f :=
     by
     rintro ⟨a₁, b₁, c₁⟩ h₁ ⟨a₂, b₂, c₂⟩ h₂ h
-    simp_rw [Prod.ext_iff] at h
+    simp_rw [Prod.ext_iff] at h 
     obtain ⟨h, rfl, rfl⟩ := h
     rw [mul_right_cancel h.1]
   rw [← card_image_of_inj_on this]

327c3c0d

bump to nightly-2023-05-28-06

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

ba5d8b97

Diff

@@ -153,12 +153,6 @@ section CommMonoid
 
 variable [CommMonoid α]
 
-/- warning: finset.multiplicative_energy_comm -> Finset.multiplicativeEnergy_comm is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] [_inst_2 : CommMonoid.{u1} α] (s : Finset.{u1} α) (t : Finset.{u1} α), Eq.{1} Nat (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toHasMul.{u1} α (Monoid.toMulOneClass.{u1} α (CommMonoid.toMonoid.{u1} α _inst_2))) s t) (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toHasMul.{u1} α (Monoid.toMulOneClass.{u1} α (CommMonoid.toMonoid.{u1} α _inst_2))) t s)
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] [_inst_2 : CommMonoid.{u1} α] (s : Finset.{u1} α) (t : Finset.{u1} α), Eq.{1} Nat (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toMul.{u1} α (Monoid.toMulOneClass.{u1} α (CommMonoid.toMonoid.{u1} α _inst_2))) s t) (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toMul.{u1} α (Monoid.toMulOneClass.{u1} α (CommMonoid.toMonoid.{u1} α _inst_2))) t s)
-Case conversion may be inaccurate. Consider using '#align finset.multiplicative_energy_comm Finset.multiplicativeEnergy_commₓ'. -/
 @[to_additive additive_energy_comm]
 theorem multiplicativeEnergy_comm (s t : Finset α) :
     multiplicativeEnergy s t = multiplicativeEnergy t s :=
@@ -174,12 +168,6 @@ section CommGroup
 
 variable [CommGroup α] [Fintype α] (s t : Finset α)
 
-/- warning: finset.multiplicative_energy_univ_left -> Finset.multiplicativeEnergy_univ_left is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] [_inst_2 : CommGroup.{u1} α] [_inst_3 : Fintype.{u1} α] (t : Finset.{u1} α), Eq.{1} Nat (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toHasMul.{u1} α (Monoid.toMulOneClass.{u1} α (DivInvMonoid.toMonoid.{u1} α (Group.toDivInvMonoid.{u1} α (CommGroup.toGroup.{u1} α _inst_2))))) (Finset.univ.{u1} α _inst_3) t) (HMul.hMul.{0, 0, 0} Nat Nat Nat (instHMul.{0} Nat Nat.hasMul) (Fintype.card.{u1} α _inst_3) (HPow.hPow.{0, 0, 0} Nat Nat Nat (instHPow.{0, 0} Nat Nat (Monoid.Pow.{0} Nat Nat.monoid)) (Finset.card.{u1} α t) (OfNat.ofNat.{0} Nat 2 (OfNat.mk.{0} Nat 2 (bit0.{0} Nat Nat.hasAdd (One.one.{0} Nat Nat.hasOne))))))
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] [_inst_2 : CommGroup.{u1} α] [_inst_3 : Fintype.{u1} α] (t : Finset.{u1} α), Eq.{1} Nat (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toMul.{u1} α (Monoid.toMulOneClass.{u1} α (DivInvMonoid.toMonoid.{u1} α (Group.toDivInvMonoid.{u1} α (CommGroup.toGroup.{u1} α _inst_2))))) (Finset.univ.{u1} α _inst_3) t) (HMul.hMul.{0, 0, 0} Nat Nat Nat (instHMul.{0} Nat instMulNat) (Fintype.card.{u1} α _inst_3) (HPow.hPow.{0, 0, 0} Nat Nat Nat (instHPow.{0, 0} Nat Nat instPowNat) (Finset.card.{u1} α t) (OfNat.ofNat.{0} Nat 2 (instOfNatNat 2))))
-Case conversion may be inaccurate. Consider using '#align finset.multiplicative_energy_univ_left Finset.multiplicativeEnergy_univ_leftₓ'. -/
 /- ./././Mathport/Syntax/Translate/Expr.lean:177:8: unsupported: ambiguous notation -/
 /- ./././Mathport/Syntax/Translate/Expr.lean:177:8: unsupported: ambiguous notation -/
 @[simp, to_additive additive_energy_univ_left]
@@ -204,12 +192,6 @@ theorem multiplicativeEnergy_univ_left :
 #align finset.multiplicative_energy_univ_left Finset.multiplicativeEnergy_univ_left
 #align finset.additive_energy_univ_left Finset.additiveEnergy_univ_left
 
-/- warning: finset.multiplicative_energy_univ_right -> Finset.multiplicativeEnergy_univ_right is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] [_inst_2 : CommGroup.{u1} α] [_inst_3 : Fintype.{u1} α] (s : Finset.{u1} α), Eq.{1} Nat (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toHasMul.{u1} α (Monoid.toMulOneClass.{u1} α (DivInvMonoid.toMonoid.{u1} α (Group.toDivInvMonoid.{u1} α (CommGroup.toGroup.{u1} α _inst_2))))) s (Finset.univ.{u1} α _inst_3)) (HMul.hMul.{0, 0, 0} Nat Nat Nat (instHMul.{0} Nat Nat.hasMul) (Fintype.card.{u1} α _inst_3) (HPow.hPow.{0, 0, 0} Nat Nat Nat (instHPow.{0, 0} Nat Nat (Monoid.Pow.{0} Nat Nat.monoid)) (Finset.card.{u1} α s) (OfNat.ofNat.{0} Nat 2 (OfNat.mk.{0} Nat 2 (bit0.{0} Nat Nat.hasAdd (One.one.{0} Nat Nat.hasOne))))))
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] [_inst_2 : CommGroup.{u1} α] [_inst_3 : Fintype.{u1} α] (s : Finset.{u1} α), Eq.{1} Nat (Finset.multiplicativeEnergy.{u1} α (fun (a : α) (b : α) => _inst_1 a b) (MulOneClass.toMul.{u1} α (Monoid.toMulOneClass.{u1} α (DivInvMonoid.toMonoid.{u1} α (Group.toDivInvMonoid.{u1} α (CommGroup.toGroup.{u1} α _inst_2))))) s (Finset.univ.{u1} α _inst_3)) (HMul.hMul.{0, 0, 0} Nat Nat Nat (instHMul.{0} Nat instMulNat) (Fintype.card.{u1} α _inst_3) (HPow.hPow.{0, 0, 0} Nat Nat Nat (instHPow.{0, 0} Nat Nat instPowNat) (Finset.card.{u1} α s) (OfNat.ofNat.{0} Nat 2 (instOfNatNat 2))))
-Case conversion may be inaccurate. Consider using '#align finset.multiplicative_energy_univ_right Finset.multiplicativeEnergy_univ_rightₓ'. -/
 @[simp, to_additive additive_energy_univ_right]
 theorem multiplicativeEnergy_univ_right :
     multiplicativeEnergy s univ = Fintype.card α * s.card ^ 2 := by

327c3c0d

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

509de852

chore: replace λ by fun (#11301)

Per the style guidelines, λ is disallowed in mathlib. This is close to exhaustive; I left some tactic code alone when it seemed to me that tactic could be upstreamed soon.

Notes

In lines I was modifying anyway, I also converted => to ↦.
Also contains some mild in-passing indentation fixes in Mathlib/Order/SupClosed.
Some doc comments still contained Lean 3 syntax λ x, , which I also replaced.

af0f54a9

Diff

@@ -17,8 +17,8 @@ additive combinatorics.
 ## TODO
 
 It's possibly interesting to have
-`(s ×ˢ s) ×ˢ t ×ˢ t).filter (λ x : (α × α) × α × α, x.1.1 * x.2.1 = x.1.2 * x.2.2)` (whose `card`
-is `multiplicativeEnergy s t`) as a standalone definition.
+`(s ×ˢ s) ×ˢ t ×ˢ t).filter (fun x : (α × α) × α × α ↦ x.1.1 * x.2.1 = x.1.2 * x.2.2)`
+(whose `card` is `multiplicativeEnergy s t`) as a standalone definition.
 -/

509de852

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

@@ -73,7 +73,7 @@ theorem le_multiplicativeEnergy : s.card * t.card ≤ multiplicativeEnergy s t :
   rw [← card_product]
   refine'
     card_le_card_of_inj_on (@fun x => ((x.1, x.1), x.2, x.2)) (by
-    -- porting note: changed this from a `simp` proof without `only` because of a timeout
+    -- Porting note: changed this from a `simp` proof without `only` because of a timeout
       simp only [ ← and_imp, mem_product, and_imp, Prod.forall, mem_filter,
         and_self, and_true, imp_self, implies_true]) fun a _ b _ => _
   simp only [Prod.mk.inj_iff, and_self_iff, and_imp]

509de852

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

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

38bce757

Diff

@@ -154,7 +154,7 @@ theorem multiplicativeEnergy_univ_left :
   congr with a
   simp only [mem_filter, mem_product, mem_univ, true_and_iff, mem_image, exists_prop,
     Prod.exists]
-  refine' ⟨fun h => ⟨a.1.1 * a.2.2⁻¹, _, _, h.1, by simp [mul_right_comm, h.2]⟩, _⟩
+  refine' ⟨fun h => ⟨a.1.1 * a.2.2⁻¹, _, _, h.1, by simp [f, mul_right_comm, h.2]⟩, _⟩
   rintro ⟨b, c, d, hcd, rfl⟩
   simpa [mul_right_comm]
 #align finset.multiplicative_energy_univ_left Finset.multiplicativeEnergy_univ_left

509de852

chore: Improve Finset lemma names (#8894)

Change a few lemma names that have historically bothered me.

Finset.card_le_of_subset → Finset.card_le_card
Multiset.card_le_of_le → Multiset.card_le_card
Multiset.card_lt_of_lt → Multiset.card_lt_card
Set.ncard_le_of_subset → Set.ncard_le_ncard
Finset.image_filter → Finset.filter_image
CompleteLattice.finset_sup_compact_of_compact → CompleteLattice.isCompactElement_finset_sup

7d3d6e43

Diff

@@ -48,7 +48,7 @@ def multiplicativeEnergy (s t : Finset α) : ℕ :=
 @[to_additive additiveEnergy_mono]
 theorem multiplicativeEnergy_mono (hs : s₁ ⊆ s₂) (ht : t₁ ⊆ t₂) :
     multiplicativeEnergy s₁ t₁ ≤ multiplicativeEnergy s₂ t₂ :=
-  card_le_of_subset <|
+  card_le_card <|
     filter_subset_filter _ <|
       product_subset_product (product_subset_product hs hs) <| product_subset_product ht ht
 #align finset.multiplicative_energy_mono Finset.multiplicativeEnergy_mono

509de852

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

@@ -24,11 +24,11 @@ is `multiplicativeEnergy s t`) as a standalone definition.
 
 section
 
-variable {α : Type _} [PartialOrder α] {x y : α}
+variable {α : Type*} [PartialOrder α] {x y : α}
 
 end
 
-variable {α : Type _} [DecidableEq α]
+variable {α : Type*} [DecidableEq α]
 
 namespace Finset

509de852

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

@@ -2,15 +2,12 @@
 Copyright (c) 2022 Yaël Dillies, Ella Yu. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Yaël Dillies, Ella Yu
-
-! This file was ported from Lean 3 source module combinatorics.additive.energy
-! leanprover-community/mathlib commit 509de852e1de55e1efa8eacfa11df0823f26f226
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Data.Finset.Prod
 import Mathlib.Data.Fintype.Prod
 
+#align_import combinatorics.additive.energy from "leanprover-community/mathlib"@"509de852e1de55e1efa8eacfa11df0823f26f226"
+
 /-!
 # Additive energy

509de852

refactor: use the typeclass SProd to implement overloaded notation · ×ˢ · (#4200)

Currently, the following notations are changed from · ×ˢ · because Lean 4 can't deal with ambiguous notations. | Definition | Notation | | :

Co-authored-by: Jeremy Tan Jie Rui <reddeloostw@gmail.com> Co-authored-by: Kyle Miller <kmill31415@gmail.com> Co-authored-by: Chris Hughes <chrishughes24@gmail.com>

6c01dc6e

Diff

@@ -20,8 +20,8 @@ additive combinatorics.
 ## TODO
 
 It's possibly interesting to have
-`(s ×ˢ s) ×ᶠ t ×ᶠ t).filter (λ x : (α × α) × α × α, x.1.1 * x.2.1 = x.1.2 * x.2.2)` (whose `card` is
-`multiplicativeEnergy s t`) as a standalone definition.
+`(s ×ˢ s) ×ˢ t ×ˢ t).filter (λ x : (α × α) × α × α, x.1.1 * x.2.1 = x.1.2 * x.2.2)` (whose `card`
+is `multiplicativeEnergy s t`) as a standalone definition.
 -/
 
 
@@ -38,14 +38,13 @@ namespace Finset
 section Mul
 
 variable [Mul α] {s s₁ s₂ t t₁ t₂ : Finset α}
--- porting note: replaced `xˢ` by `xᶠ`
 /-- The multiplicative energy of two finsets `s` and `t` in a group is the number of quadruples
 `(a₁, a₂, b₁, b₂) ∈ s × s × t × t` such that `a₁ * b₁ = a₂ * b₂`. -/
 @[to_additive additiveEnergy
       "The additive energy of two finsets `s` and `t` in a group is the
       number of quadruples `(a₁, a₂, b₁, b₂) ∈ s × s × t × t` such that `a₁ + b₁ = a₂ + b₂`."]
 def multiplicativeEnergy (s t : Finset α) : ℕ :=
-  (((s ×ᶠ s) ×ᶠ t ×ᶠ t).filter fun x : (α × α) × α × α => x.1.1 * x.2.1 = x.1.2 * x.2.2).card
+  (((s ×ˢ s) ×ˢ t ×ˢ t).filter fun x : (α × α) × α × α => x.1.1 * x.2.1 = x.1.2 * x.2.2).card
 #align finset.multiplicative_energy Finset.multiplicativeEnergy
 #align finset.additive_energy Finset.additiveEnergy
 
@@ -144,13 +143,12 @@ section CommGroup
 
 variable [CommGroup α] [Fintype α] (s t : Finset α)
 
--- porting note: replaced `xˢ` by `xᶠ`
 @[to_additive (attr := simp) additiveEnergy_univ_left]
 theorem multiplicativeEnergy_univ_left :
     multiplicativeEnergy univ t = Fintype.card α * t.card ^ 2 := by
   simp only [multiplicativeEnergy, univ_product_univ, Fintype.card, sq, ← card_product]
   let f : α × α × α → (α × α) × α × α := fun x => ((x.1 * x.2.2, x.1 * x.2.1), x.2)
-  have : (↑((univ : Finset α) ×ᶠ t ×ᶠ t) : Set (α × α × α)).InjOn f := by
+  have : (↑((univ : Finset α) ×ˢ t ×ˢ t) : Set (α × α × α)).InjOn f := by
     rintro ⟨a₁, b₁, c₁⟩ _ ⟨a₂, b₂, c₂⟩ h₂ h
     simp_rw [Prod.ext_iff] at h
     obtain ⟨h, rfl, rfl⟩ := h

509de852

feat: port Combinatorics.Additive.Energy (#1702)

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

8e030b69

`combinatorics.additive.energy` ⟷ `Mathlib.Combinatorics.Additive.Energy`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 2 + 167

combinatorics.additive.energy ⟷ Mathlib.Combinatorics.Additive.Energy

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 2 + 167

`combinatorics.additive.energy` ⟷ `Mathlib.Combinatorics.Additive.Energy`