PFRPalomar/Challenge.lean
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Project sources: Pinned project documentation, Polynomial Freiman-Ruzsa proof paper, arXiv v2
6 declarations, 6 contain sorry, 0 declared as axioms
Marton's conjecture (the polynomial Freiman–Ruzsa conjecture)
This file states, in Mathlib-only terms, the headline theorems of three papers:
[GGMT]W. T. Gowers, Ben Green, Freddie Manners, Terence Tao, On a conjecture of Marton, arXiv:2311.05762.[GGMT2]W. T. Gowers, Ben Green, Freddie Manners, Terence Tao, Marton's conjecture in abelian groups with bounded torsion, arXiv:2404.02244.[L]Jyun-Jie Liao, Improved exponent for Marton's conjecture in $\mathbf{F}_2^n$, arXiv:2404.09639.
Marton's conjecture, widely known as the polynomial Freiman–Ruzsa conjecture, asserts that a
subset A of an abelian group with small doubling, |A + A| ≤ K * |A|, is efficiently covered
by cosets of a subgroup no larger than A, with a number of cosets polynomial in K.
The six statements below are:
Marton.pfr_conjecture—[GGMT], Theorem 1.2: the conjecture in𝔽₂ⁿ, with2 * K ^ 12cosets.Marton.pfr_conjecture_nine—[L], main theorem: the same conclusion with2 * K ^ 9cosets. This strengthensMarton.pfr_conjecture, which is retained because it is the headline theorem of a different paper.Marton.torsion_pfr_conjecture—[GGMT2], Theorem 1.1: the conjecture in an arbitrary abelian group of torsionm, withm * K ^ (256 * m ^ 3 + 1)cosets.Marton.weak_pfr_int—[GGMT], Theorem 1.3: a set of small doubling in a finitely generated freeℤ-module has a large subset of logarithmically small affine dimension.Marton.homomorphism_pfr—[GGMT], Corollary 1.4: a map whose additive defects take few values differs from a homomorphism by a map with small range.Marton.approx_hom_pfr—[GGMT], Corollary 1.5: a map that is additive on a positive proportion of pairs agrees with a homomorphism on a positive proportion of points.
All statements are phrased with Nat.card, Set pointwise arithmetic, AddSubgroup,
vectorSpan and Module.finrank, so that no definition of this project is needed in order to
read them. Torsion hypotheses are stated as ∀ x : G, m • x = 0 rather than through a
Module (ZMod m) G instance, so that the statements do not depend on which ZMod-algebra
instance path is in scope.
Imports (6)
- theorem
Marton.pfr_conjectureMarton's conjecture in characteristic 2,[GGMT], Theorem 1.2 sorry line 69 sourceSource documentation
Marton's conjecture in characteristic 2,
[GGMT], Theorem 1.2.If
Ais a finite non-empty subset of an abelian groupGof exponent2— that is,2 • x = 0for everyx : G, so thatGis an𝔽₂-vector space — and|A + A| ≤ K * |A|, thenAis covered by fewer than2 * K ^ 12cosets of a subgroupHofGwith|H| ≤ |A|.The ambient group
Gis not required to be finite; the covering setcand the subgroupHproduced are then finite. This statement is superseded byMarton.pfr_conjecture_nine, and is recorded separately because it is the headline theorem of[GGMT].depends on sorry what this means
Statement uses:
AddCommGroup,Eq,HSMul.hSMul,Nat,OfNat.ofNat,Set,Set.Finite,Set.Nonempty,Real,LE.le,Nat.card,HAdd.hAdd,HMul.hMul,Exists,AddSubgroup,And,LT.lt,HPow.hPow,Subtype,Membership.memProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous76 instances, coercions and auxiliary constants left out.
Distinct definitions of this name: PFRPalomar/Solution.lean:33 (same statement text; different proof or body). Qualify references as Marton.pfr_conjecture@path.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem pfr_conjecture {G : Type*} [AddCommGroup G] (h2 : ∀ x : G, 2 • x = 0) {A : Set G} (hA : A.Finite) (hA₀ : A.Nonempty) {K : ℝ} (hAK : Nat.card (A + A) ≤ K * Nat.card A) : ∃ (H : AddSubgroup G) (c : Set G), c.Finite ∧ (H : Set G).Finite ∧ Nat.card c < 2 * K ^ 12 ∧ Nat.card H ≤ Nat.card A ∧ A ⊆ c + H := by … - theorem
Marton.pfr_conjecture_nineMarton's conjecture in characteristic 2 with exponent 9,[L], main theorem sorry line 84 sourceSource documentation
Marton's conjecture in characteristic 2 with exponent 9,
[L], main theorem.If
Ais a finite non-empty subset of an abelian groupGof exponent2— that is,2 • x = 0for everyx : G, so thatGis an𝔽₂-vector space — and|A + A| ≤ K * |A|, thenAis covered by fewer than2 * K ^ 9cosets of a subgroupHofGwith|H| ≤ |A|.The ambient group
Gis not required to be finite; the covering setcand the subgroupHproduced are then finite.depends on sorry what this means
Statement uses:
AddCommGroup,Eq,HSMul.hSMul,Nat,OfNat.ofNat,Set,Set.Finite,Set.Nonempty,Real,LE.le,Nat.card,HAdd.hAdd,HMul.hMul,Exists,AddSubgroup,And,LT.lt,HPow.hPow,Subtype,Membership.memProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous76 instances, coercions and auxiliary constants left out.
Distinct definitions of this name: PFRPalomar/Solution.lean:48 (same statement text; different proof or body). Qualify references as Marton.pfr_conjecture_nine@path.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem pfr_conjecture_nine {G : Type*} [AddCommGroup G] (h2 : ∀ x : G, 2 • x = 0) {A : Set G} (hA : A.Finite) (hA₀ : A.Nonempty) {K : ℝ} (hAK : Nat.card (A + A) ≤ K * Nat.card A) : ∃ (H : AddSubgroup G) (c : Set G), c.Finite ∧ (H : Set G).Finite ∧ Nat.card c < 2 * K ^ 9 ∧ Nat.card H ≤ Nat.card A ∧ A ⊆ c + H := by … - theorem
Marton.torsion_pfr_conjectureMarton's conjecture in abelian groups of bounded torsion,[GGMT2], Theorem 1.1 sorry line 98 sourceSource documentation
Marton's conjecture in abelian groups of bounded torsion,
[GGMT2], Theorem 1.1.Let
Gbe an abelian group of torsionm ≥ 2, meaning thatm • x = 0for everyx : G. IfAis a finite non-empty subset ofGwith|A + A| ≤ K * |A|, thenAis covered by fewer thanm * K ^ (256 * m ^ 3 + 1)cosets of a subgroupHofGwith|H| ≤ |A|.The ambient group
Gis not required to be finite; the covering setcand the subgroupHproduced are then finite.depends on sorry what this means
Statement uses:
AddCommGroup,Nat,LE.le,OfNat.ofNat,Eq,HSMul.hSMul,Set,Set.Finite,Set.Nonempty,Real,Nat.card,HAdd.hAdd,HMul.hMul,Exists,AddSubgroup,And,LT.lt,HPow.hPow,Subtype,Membership.memProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous76 instances, coercions and auxiliary constants left out.
Distinct definitions of this name: PFRPalomar/Solution.lean:55 (same statement text; different proof or body). Qualify references as Marton.torsion_pfr_conjecture@path.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem torsion_pfr_conjecture {G : Type*} [AddCommGroup G] {m : ℕ} (hm : 2 ≤ m) (htorsion : ∀ x : G, m • x = 0) {A : Set G} (hA : A.Finite) (hA₀ : A.Nonempty) {K : ℝ} (hAK : Nat.card (A + A) ≤ K * Nat.card A) : ∃ (H : AddSubgroup G) (c : Set G), c.Finite ∧ (H : Set G).Finite ∧ Nat.card c < m * K ^ (256 * m ^ 3 + 1) ∧ Nat.card H ≤ Nat.card A ∧ A ⊆ c + H := by … - theorem
Marton.weak_pfr_intWeak Marton's conjecture over the integers,[GGMT], Theorem 1.3 sorry line 114 sourceSource documentation
Weak Marton's conjecture over the integers,
[GGMT], Theorem 1.3.Let
Gbe a finitely generated freeℤ-module, that is, a copy ofℤ ^ D. IfAis a finite non-empty subset ofGwith|A + A| ≤ K * |A|, thenAhas a subsetA'with|A'| ≥ K ^ (-34) * |A|whose affine dimension — the rank of theℤ-span of its difference set — is at most(80 / log 2) * log K.This realises the constants
C₁ = 34andC₂ = 80 / log 2of[GGMT], Theorem 1.3, which is stated there for unspecified absolute constants.depends on sorry what this means
Statement uses:
AddCommGroup,Module.Free,Int,Module.Finite,Set,Set.Finite,Set.Nonempty,Real,LE.le,Nat.card,HAdd.hAdd,HMul.hMul,Exists,And,HPow.hPow,Neg.neg,OfNat.ofNat,Nat,Module.finrank,Subtypeand 5 moreProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous66 instances, coercions and auxiliary constants left out.
Distinct definitions of this name: PFRPalomar/Solution.lean:63 (same statement text; different proof or body). Qualify references as Marton.weak_pfr_int@path.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem weak_pfr_int {G : Type*} [AddCommGroup G] [Module.Free ℤ G] [Module.Finite ℤ G] {A : Set G} (hA : A.Finite) (hA₀ : A.Nonempty) {K : ℝ} (hAK : Nat.card (A + A) ≤ K * Nat.card A) : ∃ A' ⊆ A, K ^ (-34 : ℝ) * Nat.card A ≤ Nat.card A' ∧ (Module.finrank ℤ (vectorSpan ℤ A') : ℝ) ≤ (80 / Real.log 2) * Real.log K := by … - theorem
Marton.homomorphism_pfrThe homomorphism form of Marton's conjecture,[GGMT], Corollary 1.4 sorry line 126 sourceSource documentation
The homomorphism form of Marton's conjecture,
[GGMT], Corollary 1.4.Let
GandG'be finite abelian groups of exponent2and letf : G → G'be a function whose additive defectsf (x + y) - f x - f yall lie in a setS. Thenfdiffers from a group homomorphismφ : G →+ G'by a function taking at most|S| ^ 10values.depends on sorry what this means
Statement uses:
AddCommGroup,Finite,Eq,HSMul.hSMul,Nat,OfNat.ofNat,Set,Membership.mem,HSub.hSub,HAdd.hAdd,Exists,AddMonoidHom,And,LE.le,Nat.card,HPow.hPowProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous62 instances, coercions and auxiliary constants left out.
Distinct definitions of this name: PFRPalomar/Solution.lean:77 (same statement text; different proof or body). Qualify references as Marton.homomorphism_pfr@path.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem homomorphism_pfr {G G' : Type*} [AddCommGroup G] [AddCommGroup G'] [Finite G] [Finite G'] (h2 : ∀ x : G, 2 • x = 0) (h2' : ∀ y : G', 2 • y = 0) (f : G → G') (S : Set G') (hS : ∀ x y : G, f (x + y) - f x - f y ∈ S) : ∃ (φ : G →+ G') (T : Set G'), Nat.card T ≤ Nat.card S ^ 10 ∧ ∀ x : G, f x - φ x ∈ T := by … - theorem
Marton.approx_hom_pfrThe approximate homomorphism form of Marton's conjecture,[GGMT], Corollary 1.5 sorry line 139 sourceSource documentation
The approximate homomorphism form of Marton's conjecture,
[GGMT], Corollary 1.5.Let
GandG'be finite abelian groups of exponent2and letf : G → G'be a function such thatf (x + y) = f x + f yfor at least a proportionK⁻¹of the pairs(x, y) ∈ G × G, written here as|G| ^ 2 ≤ K * |{(x, y) | f (x + y) = f x + f y}|. Then there is a group homomorphismφ : G →+ G'agreeing withfon at least(|G| / (2 ^ 144 * K ^ 122) - 1) / 2points ofG.depends on sorry what this means
Statement uses:
AddCommGroup,Finite,Eq,HSMul.hSMul,Nat,OfNat.ofNat,Real,LT.lt,LE.le,HPow.hPow,Nat.card,HMul.hMul,Prod,Set.ofPred,HAdd.hAdd,Prod.fst,Prod.snd,Exists,AddMonoidHom,HDiv.hDivand 1 moreProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous88 instances, coercions and auxiliary constants left out.
Distinct definitions of this name: PFRPalomar/Solution.lean:106 (same statement text; different proof or body). Qualify references as Marton.approx_hom_pfr@path.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem approx_hom_pfr {G G' : Type*} [AddCommGroup G] [AddCommGroup G'] [Finite G] [Finite G'] (h2 : ∀ x : G, 2 • x = 0) (h2' : ∀ y : G', 2 • y = 0) (f : G → G') {K : ℝ} (hK : 0 < K) (hf : (Nat.card G : ℝ) ^ 2 ≤ K * Nat.card {x : G × G | f (x.1 + x.2) = f x.1 + f x.2}) : ∃ φ : G →+ G', (Nat.card G / (2 ^ 144 * K ^ 122) - 1) / 2 ≤ Nat.card {x : G | f x = φ x} := by …