openAI-math-dataset / lean /OAI /Geometry /HeilbronnTriangle /AuxiliarySamplingLaw.lean
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import OAI.Geometry.HeilbronnTriangle.AuxiliaryAffineWeights
import OAI.Geometry.HeilbronnTriangle.AuxiliarySet
import OAI.Geometry.HeilbronnTriangle.LiftingProbability
namespace OAI
noncomputable section
namespace Problem355.AuxiliarySampling
open scoped BigOperators
structure Law (q H : ℕ) [Fact q.Prime] where
Outcome : Type
outcomeFintype : Fintype Outcome
weight : Outcome → ℝ
sets : Outcome → Finset (Fin 3 → ZMod q)
size : ℕ
size_pos : 0 < size
weight_nonneg : ∀ ω, 0 ≤ weight ω
weight_sum : @Finset.sum Outcome ℝ _ (@Finset.univ Outcome outcomeFintype) weight = 1
sets_card : ∀ ω, (sets ω).card = size
size_lower : q ^ 2 ≤ 2000 ^ 3 * H ^ 6 * size
zero_not_mem : ∀ ω, (0 : Fin 3 → ZMod q) ∉ sets ω
isCap : ∀ ω, AuxiliaryCap.IsCap (sets ω : Set (Fin 3 → ZMod q))
short_relation : ∀ ω (p : Fin 3 → (Fin 3 → ZMod q)),
(∀ i, p i ∈ sets ω) → Function.Injective p →
∀ x : Fin 3 → ℤ, (∀ i, |x i| ≤ (H : ℤ)) → x ≠ 0 →
(∑ i, (x i : ZMod q) • p i) ≠ 0
weight_le_eight : ∀ p : Fin 3 → (Fin 3 → ZMod q),
AffineIndependent (ZMod q) p →
@LiftingProbability.auxiliaryWeight Outcome (Fin 3 → ZMod q) outcomeFintype
q size weight sets p ≤ 8
weight_le_four : ∀ (p : Fin 3 → (Fin 3 → ZMod q)) (i j : Fin 3), p i ≠ p j →
@LiftingProbability.auxiliaryWeight Outcome (Fin 3 → ZMod q) outcomeFintype
q size weight sets p ≤ 4 * ((q : ℝ) ^ 3 / size)
weight_le_two : ∀ p : Fin 3 → (Fin 3 → ZMod q),
@LiftingProbability.auxiliaryWeight Outcome (Fin 3 → ZMod q) outcomeFintype
q size weight sets p ≤ 2 * ((q : ℝ) ^ 3 / size) ^ 2
attribute [instance] Law.outcomeFintype
private theorem affine_apply_inputShift {q : ℕ} [Fact q.Prime]
(e : (Fin 3 → ZMod q) ≃ᵃ[ZMod q] (Fin 3 → ZMod q))
(x : Fin 3 → ZMod q) :
e x = (AffineTripleOrbit.inputShiftEquiv e).1
((AffineTripleOrbit.inputShiftEquiv e).2 + x) := by
have h := congrArg
(fun f : (Fin 3 → ZMod q) ≃ᵃ[ZMod q] (Fin 3 → ZMod q) => f x)
(AffineTripleOrbit.inputShiftEquiv.symm_apply_apply e)
exact h.symm.trans (AffineTripleOrbit.inputShiftEquiv_symm_apply
(AffineTripleOrbit.inputShiftEquiv e).1 (AffineTripleOrbit.inputShiftEquiv e).2 x)
theorem nonempty_law_of_cap {q H w : ℕ} [Fact q.Prime]
(hH : 1 ≤ H) (hHq : H < q)
(S : Finset (Fin 3 → ZMod q)) (hS : S.Nonempty)
(hcap : AuxiliaryCap.IsCap (S : Set (Fin 3 → ZMod q)))
(hbox : ∀ v ∈ S, (v 0).val < w)
(hsize : q ^ 2 ≤ 2000 ^ 3 * H ^ 6 * S.card)
(A : Finset (Fin 3 → ZMod q)) (hA : q ^ 3 ≤ 2 * A.card)
(hallowed : ∀ a ∈ A, ∀ n : ℕ, 1 ≤ n → n ≤ 3 * H →
(n : ZMod q) * a 0 ∉ Auxiliary.integerWindow q (3 * H * w)) :
Nonempty (Law q H) := by
classical
let Aff := (Fin 3 → ZMod q) ≃ᵃ[ZMod q] (Fin 3 → ZMod q)
let : Finite Aff := Finite.of_injective
(fun e : Aff => (e : (Fin 3 → ZMod q) → (Fin 3 → ZMod q)))
DFunLike.coe_injective
let : Fintype Aff := Fintype.ofFinite Aff
let T : Finset Aff := AuxiliaryWeights.affineMapsWithInputShift A
have hA' : Fintype.card (Fin 3 → ZMod q) ≤ 2 * A.card := by
simpa using hA
have hT : T.Nonempty := AuxiliaryWeights.affineMapsWithInputShift_nonempty A hA'
have hTsize : Fintype.card Aff ≤ 2 * T.card :=
AuxiliaryWeights.affineMapsWithInputShift_halfDensity A hA'
let μ : T → ℝ := fun _ => (T.card : ℝ)⁻¹
let V : T → Finset (Fin 3 → ZMod q) := fun e => S.image e.1
have hV (e : T) : V e = AuxiliarySet.transformed S
(AffineTripleOrbit.inputShiftEquiv e.1).2
(AffineTripleOrbit.inputShiftEquiv e.1).1 := by
ext y
simp only [V, Finset.mem_image, AuxiliarySet.mem_transformed]
constructor
· rintro ⟨x, hx, rfl⟩
exact ⟨x, hx, (affine_apply_inputShift e.1 x).symm⟩
· rintro ⟨x, hx, rfl⟩
exact ⟨x, hx, affine_apply_inputShift e.1 x⟩
have hall (e : T) : ∀ n : ℕ, 1 ≤ n → n ≤ 3 * H →
(n : ZMod q) * (AffineTripleOrbit.inputShiftEquiv e.1).2 0 ∉
Auxiliary.integerWindow q (3 * H * w) := by
apply hallowed
exact (Finset.mem_filter.mp e.2).2
have hprops (e : T) := AuxiliarySet.transformed_properties hH hHq hcap hbox
(AffineTripleOrbit.inputShiftEquiv e.1).2 (hall e)
(AffineTripleOrbit.inputShiftEquiv e.1).1
have hW (p : Fin 3 → (Fin 3 → ZMod q)) :
LiftingProbability.auxiliaryWeight q S.card μ V p =
AuxiliaryWeights.affineInclusionWeight S T p := by
rw [AuxiliaryWeights.affineInclusionWeight_eq_uniform_sum]
simp only [LiftingProbability.auxiliaryWeight, LiftingProbability.inclusionMass,
ZMod.card]
congr 1
apply Finset.sum_congr rfl
intro e he
simp only [LiftingProbability.TripleIn, μ, V, Finset.mem_image]
split_ifs <;> simp_all
refine ⟨{
Outcome := T
outcomeFintype := inferInstance
weight := μ
sets := V
size := S.card
size_pos := hS.card_pos
weight_nonneg := ?_
weight_sum := ?_
sets_card := ?_
size_lower := hsize
zero_not_mem := ?_
isCap := ?_
short_relation := ?_
weight_le_eight := ?_
weight_le_four := ?_
weight_le_two := ?_ }⟩
· intro e
dsimp [μ]
positivity
· simp only [μ, Finset.sum_const, Finset.card_univ, Fintype.card_coe, nsmul_eq_mul]
exact mul_inv_cancel₀ (by exact_mod_cast hT.card_pos.ne')
· intro e
rw [hV]
exact (hprops e).1
· intro e
rw [hV]
exact (hprops e).2.1
· intro e
rw [hV]
exact (hprops e).2.2.1
· intro e p hp hinj x hx hne
exact (hprops e).2.2.2 p (fun i => hV e ▸ hp i) hinj x hx hne
· intro p hp
rw [hW]
exact AuxiliaryWeights.affineInclusionWeight_le_eight S hS T hT hTsize p hp
· intro p i j hp
rw [hW]
simpa only [ZMod.card] using
AuxiliaryWeights.affineInclusionWeight_le_four_of_ne S hS T hT hTsize p i j hp
· intro p
rw [hW]
simpa only [ZMod.card] using
AuxiliaryWeights.affineInclusionWeight_le_two S hS T hT hTsize p
theorem nonempty_law {q H : ℕ} [Fact q.Prime]
(hH : 1 ≤ H) (hq : 2000 * H ^ 2 ≤ q) : Nonempty (Law q H) := by
classical
let w := q / (1000 * H ^ 2)
have hd : 0 < 1000 * H ^ 2 := by positivity
have hdq : 1000 * H ^ 2 ≤ q := by omega
have hwq : w ≤ q := Nat.div_le_self _ _
have hq2 : q ≠ 2 := by
have hHsq : 1 ≤ H ^ 2 := by nlinarith
omega
obtain ⟨S, hbox, hsize, hcap⟩ := AuxiliaryCap.exists_cap_in_residueBox hq2 hwq
have hfloor : q ≤ 2000 * H ^ 2 * w := by
calc
q ≤ 2 * (1000 * H ^ 2) * w := AuxiliarySet.le_twice_mul_div hd hdq
_ = 2000 * H ^ 2 * w := by ring
have hc : q ^ 2 ≤ 2000 ^ 3 * H ^ 6 * S.card := by
have hcube : q ^ 3 ≤ (2000 * H ^ 2 * w) ^ 3 := by gcongr
have hm : q * q ^ 2 ≤ q * (2000 ^ 3 * H ^ 6 * S.card) := by
calc
q * q ^ 2 = q ^ 3 := by ring
_ ≤ (2000 * H ^ 2 * w) ^ 3 := hcube
_ = (2000 ^ 3 * H ^ 6) * w ^ 3 := by ring
_ ≤ (2000 ^ 3 * H ^ 6) * (q * S.card) := Nat.mul_le_mul_left _ hsize
_ = q * (2000 ^ 3 * H ^ 6 * S.card) := by ring
exact Nat.le_of_mul_le_mul_left hm (Fact.out : q.Prime).pos
have hS : S.Nonempty := by
apply Finset.card_pos.mp
by_contra hn
have hz : S.card = 0 := by omega
have hp : 0 < q ^ 2 := pow_pos (Fact.out : q.Prime).pos 2
simp only [hz, mul_zero] at hc
omega
let A := Auxiliary.vectorShifts (Auxiliary.allowedShifts
(Auxiliary.positiveMultipliers q H) (Auxiliary.integerWindow q (3 * H * w)))
have hw : 1000 * H ^ 2 * w ≤ q := Nat.mul_div_le _ _
have hA : q ^ 3 ≤ 2 * A.card :=
(Auxiliary.auxiliary_allowed_vector_card_gt_half q H w hH hq hw).le
have hmult : 3 * H < q := Auxiliary.auxiliary_multiplier_range q H hH hq
apply nonempty_law_of_cap hH (by omega) S hS hcap (fun v hv => hbox v hv 0) hc A hA
intro a ha n hn hnH
have ha' := (Auxiliary.mem_vectorShifts_iff _ a).mp ha
have ha'' := (Auxiliary.mem_allowedShifts_iff _ _
(Auxiliary.positiveMultipliers_ne_zero q H hmult) (a 0)).mp ha'
apply ha''
exact Finset.mem_image.mpr ⟨n, Finset.mem_Icc.mpr ⟨hn, hnH⟩, rfl⟩
end Problem355.AuxiliarySampling
end
end OAI