openAI-math-dataset / lean /OAI /NumberTheory /PrimeGaps /OrthantIntegrals.lean
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import OAI.NumberTheory.PrimeGaps.LevelMoments
namespace OAI
namespace LargePrimeGaps
open Filter
open Set Filter MeasureTheory
open scoped Topology ContDiff
theorem integral_eq_orthant_integral {j : ℕ} {f : (Fin j → ℝ) → ℝ}
(hf : Function.support f ⊆ {t | ∀ i, 0 < t i}) :
(∫ t, f t) = ∫ t in {t : Fin j → ℝ | ∀ i, 0 ≤ t i}, f t := by
have hm : MeasurableSet {t : Fin j → ℝ | ∀ i, 0 ≤ t i} := by
have heq : {t : Fin j → ℝ | ∀ i, 0 ≤ t i} =
⋂ i : Fin j, {t : Fin j → ℝ | 0 ≤ t i} := by ext t; simp
rw [heq]
exact MeasurableSet.iInter (fun i : Fin j =>
(isClosed_le continuous_const (continuous_apply i)).measurableSet)
rw [← integral_indicator hm]
apply integral_congr_ae
filter_upwards [] with t
by_cases ht : t ∈ {t : Fin j → ℝ | ∀ i, 0 ≤ t i}
· rw [Set.indicator_of_mem ht]
· rw [Set.indicator_of_notMem ht]
by_contra hn
exact ht (fun i => (hf hn i).le)
theorem l2Mass_eq_orthant_integral {j : ℕ} {f : (Fin j → ℝ) → ℝ}
(hf : Function.support f ⊆ {t | ∀ i, 0 < t i}) :
l2Mass f = ∫ t in {t : Fin j → ℝ | ∀ i, 0 ≤ t i}, f t^2 := by
apply integral_eq_orthant_integral
intro t ht
apply hf
exact fun h => ht (by simp only [h, zero_pow (by decide : 2 ≠ 0)])
theorem deleteCoordinate_eq_orthant_integral {j : ℕ} {f : (Fin (j+1) → ℝ) → ℝ}
(hf : Function.support f ⊆ {t | ∀ i, 0 < t i}) (t : Fin j → ℝ) :
deleteCoordinate f t = ∫ u in Ici (0:ℝ), f (Fin.snoc t u) := by
unfold deleteCoordinate
rw [← integral_indicator measurableSet_Ici]
apply integral_congr_ae
filter_upwards [] with u
by_cases hu : u ∈ Ici (0:ℝ)
· rw [Set.indicator_of_mem hu]
· rw [Set.indicator_of_notMem hu]
by_contra hn
apply hu
change 0 ≤ u
simpa only [Fin.snoc_last] using (hf hn (Fin.last j)).le
def squareDimension (m : ℕ) : ℕ := (m+1)^2
theorem squareDimension_pos (m : ℕ) : 0 < squareDimension m := by
unfold squareDimension
positivity
theorem active_length_le_squareDimension (m : ℕ) : m+1 ≤ squareDimension m := by
unfold squareDimension
nlinarith [Nat.zero_le m]
theorem squareDimension_strictMono : StrictMono squareDimension := by
intro m n hmn
unfold squareDimension
nlinarith
theorem tendsto_squareDimension : Tendsto squareDimension atTop atTop :=
squareDimension_strictMono.tendsto_atTop
theorem tendsto_inverse_squareDimension :
Tendsto (fun m : ℕ => ((squareDimension m:ℕ):ℝ)⁻¹) atTop (nhds 0) :=
(tendsto_natCast_atTop_atTop.comp tendsto_squareDimension).inv_tendsto_atTop
theorem tendsto_inverse_active_length :
Tendsto (fun m : ℕ => (((m+1):ℕ):ℝ)⁻¹) atTop (nhds 0) :=
(tendsto_natCast_atTop_atTop.comp (tendsto_add_atTop_nat 1)).inv_tendsto_atTop
theorem rectangle_error_tendsto_zero (v d : ℝ) :
Tendsto (fun m : ℕ => v/((squareDimension m:ℝ)*d^2)) atTop (nhds 0) := by
have h := tendsto_inverse_squareDimension.const_mul (v/(d^2))
simpa only [mul_zero, div_eq_mul_inv, mul_inv_rev, mul_assoc, mul_comm (d^2)⁻¹] using h
theorem square_ratio_eq_inverse (m : ℕ) :
((m+1:ℕ):ℝ)/(squareDimension m:ℝ) = ((m+1:ℕ):ℝ)⁻¹ := by
have hm : ((m+1:ℕ):ℝ) ≠ 0 := by positivity
unfold squareDimension
rw [Nat.cast_pow]
field_simp
theorem cancellation_bound_tendsto_zero (lambda v d : ℝ) :
Tendsto (fun m : ℕ => lambda * (2/((m+1:ℕ):ℝ) +
(((m+1:ℕ):ℝ)/(squareDimension m:ℝ))^2 +
4*v/((squareDimension m:ℝ)*d^2))) atTop (nhds 0) := by
have h1 := tendsto_inverse_active_length.const_mul 2
have h2 := tendsto_inverse_active_length.pow 2
have h3 := rectangle_error_tendsto_zero (4*v) d
have h := ((h1.add h2).add h3).const_mul lambda
simp only [square_ratio_eq_inverse]
simpa only [mul_zero, zero_pow (by decide : 2 ≠ 0), zero_add, div_eq_mul_inv] using h
theorem cancellationFamily_W_tendsto {g chi : ℝ → ℝ} {lambda beta : ℝ}
(hlambda : 0 < lambda) (hg : Continuous g) (hgc : HasCompactSupport g)
(hgs : Function.support g ⊆ Ioi 0) (hg2 : (∫ u, g u^2) = 1)
(hchi : Continuous chi) (hchi0 : ∀ s, 0 ≤ chi s) (hchi1 : ∀ s, chi s ≤ 1)
(hflat : ∀ s ≤ beta, chi s = 1) (hmu : (∫ u, u*g u^2) < beta) :
Tendsto (fun m => familyW lambda (squareDimension m)
(cancellationFamily g chi lambda (squareDimension m) (m+1))) atTop (nhds 1) := by
let d := beta - ∫ u, u*g u^2
let v := ∫ u, (u-∫ v, v*g v^2)^2 * g u^2
have hlo := (rectangle_error_tendsto_zero v d).const_sub 1
simp only [sub_zero] at hlo
apply tendsto_of_tendsto_of_tendsto_of_le_of_le hlo tendsto_const_nhds
· intro m
exact (cancellationFamily_W_bounds hlambda (Nat.succ_pos m)
(active_length_le_squareDimension m) hg hgc hgs hg2 hchi hchi0 hchi1 hflat hmu).1
· intro m
exact (cancellationFamily_W_bounds hlambda (Nat.succ_pos m)
(active_length_le_squareDimension m) hg hgc hgs hg2 hchi hchi0 hchi1 hflat hmu).2
theorem cancellationFamily_V_tendsto {g chi : ℝ → ℝ} {lambda beta B : ℝ}
(hlambda : 0 < lambda) (hg : Continuous g) (hgc : HasCompactSupport g)
(hgs : Function.support g ⊆ Ioi 0) (hgn : ∀ u, 0 ≤ g u)
(hg2 : (∫ u, g u^2) = 1) (hg1 : (∫ u, g u) = Real.sqrt lambda)
(hB : ∀ u ∈ Function.support g, u ≤ B) (hB0 : 0 ≤ B)
(hchi : Continuous chi) (hchi0 : ∀ s, 0 ≤ chi s) (hchi1 : ∀ s, chi s ≤ 1)
(hflat : ∀ s ≤ beta, chi s = 1) (hmu : (∫ u, u*g u^2) < beta) :
Tendsto (fun m => familyV lambda (squareDimension m)
(cancellationFamily g chi lambda (squareDimension m) (m+1))) atTop (nhds 0) := by
let d := beta - ∫ u, u*g u^2
let v := ∫ u, (u-∫ v, v*g v^2)^2 * g u^2
have hBdiv : Tendsto (fun m => B/(squareDimension m:ℝ)) atTop (nhds 0) := by
simpa only [div_eq_mul_inv, mul_zero] using tendsto_inverse_squareDimension.const_mul B
have hBk : ∀ᶠ m in atTop, B/(squareDimension m:ℝ) ≤ d/2 := by
exact ((tendsto_order.mp hBdiv).2 (d/2) (by dsimp only [d]; linarith)).mono (fun _ h => h.le)
apply squeeze_zero' (Eventually.of_forall fun m => familyV_nonneg hlambda _ _)
_ (cancellation_bound_tendsto_zero lambda v d)
filter_upwards [hBk] with m hm
exact cancellationFamily_V_bound hlambda (Nat.succ_pos m)
(active_length_le_squareDimension m) hg hgc hgs hgn hg2 hg1 hB hB0 hchi hchi0 hchi1 hflat hmu hm
def AdmissibleFamily (tau : ℝ) (k : ℕ) (f : (j : ℕ) → (Fin j → ℝ) → ℝ) : Prop :=
0 < k ∧
(∀ j, j ≤ k → ContDiff ℝ ∞ (f j) ∧ HasCompactSupport (f j) ∧
tsupport (f j) ⊆ positiveSimplex j tau ∧ SymmetricFunction (f j)) ∧
(∀ j, k < j → f j = 0)
theorem exists_canceling_families {lambda tau : ℝ} (hlambda : 0 < lambda) (htau : 0 < tau) :
∃ f : (m j : ℕ) → (Fin j → ℝ) → ℝ,
(∀ m, AdmissibleFamily tau (squareDimension m) (f m) ∧ f m 0 = 0) ∧
Tendsto (fun m => familyW lambda (squareDimension m) (f m)) atTop (nhds 1) ∧
Tendsto (fun m => familyV lambda (squareDimension m) (f m)) atTop (nhds 0) := by
let beta := tau/3
let gamma := 2*tau/3
have hb : 0 < beta := by dsimp only [beta]; positivity
have hbg : beta < gamma := by dsimp only [beta, gamma]; linarith
have hgt : gamma < tau := by dsimp only [gamma]; linarith
obtain ⟨g, hgsmooth, hgc, hgs, hgn, hg2, hg1, hmu⟩ := exists_small_first_moment_profile hlambda hb
let chi := simplexCutoff beta gamma
have hchi : ContDiff ℝ ∞ chi := simplexCutoff_smooth beta gamma
have hc0 : ∀ s, 0 ≤ chi s := simplexCutoff_nonneg beta gamma
have hc1 : ∀ s, chi s ≤ 1 := simplexCutoff_le_one beta gamma
have hcflat : ∀ s ≤ beta, chi s = 1 := fun _ hs => simplexCutoff_eq_one hbg hs
have hcz : ∀ s, gamma ≤ s → chi s = 0 := fun _ hs => simplexCutoff_eq_zero hbg hs
obtain ⟨b, hbnd⟩ := hgc.bddAbove
let B := max b 0
have hB : ∀ u ∈ Function.support g, u ≤ B := fun u hu =>
(hbnd (subset_closure hu)).trans (le_max_left b 0)
have hB0 : 0 ≤ B := le_max_right b 0
have hsupport : Function.support g ⊆ Ioi 0 := fun _ hu => hgs (subset_closure hu)
refine ⟨fun m => cancellationFamily g chi lambda (squareDimension m) (m+1), ?_, ?_, ?_⟩
· intro m
refine ⟨⟨squareDimension_pos m, ?_, ?_⟩, cancellationFamily_zero _ _ _ _ _⟩
· intro j _
exact cancellationFamily_properties (squareDimension_pos m) hgsmooth hgc hgs hchi hgt hcz j
· intro j hj
exact cancellationFamily_above _ _ _ _ _ hj
· exact cancellationFamily_W_tendsto hlambda hgsmooth.continuous hgc hsupport hg2
hchi.continuous hc0 hc1 hcflat hmu
· exact cancellationFamily_V_tendsto hlambda hgsmooth.continuous hgc hsupport hgn hg2 hg1
hB hB0 hchi.continuous hc0 hc1 hcflat hmu
theorem exists_family_small_marked_ratio {lambda tau epsilon : ℝ}
(hlambda : 0 < lambda) (htau : 0 < tau) (hepsilon : 0 < epsilon) :
∃ k : ℕ, ∃ f : (j : ℕ) → (Fin j → ℝ) → ℝ,
AdmissibleFamily tau k f ∧ f 0 = 0 ∧
0 < familyW lambda k f ∧ familyV lambda k f / familyW lambda k f ≤ epsilon := by
obtain ⟨f, hf, hW, hV⟩ := exists_canceling_families hlambda htau
have hWpos : ∀ᶠ m in atTop, 0 < familyW lambda (squareDimension m) (f m) :=
(tendsto_order.mp hW).1 0 (by norm_num)
have hratio : Tendsto (fun m => familyV lambda (squareDimension m) (f m) /
familyW lambda (squareDimension m) (f m)) atTop (nhds 0) := by
have hdiv := hV.div hW (by norm_num : (1:ℝ) ≠ 0)
rw [zero_div] at hdiv
exact hdiv
have hsmall := (tendsto_order.mp hratio).2 epsilon hepsilon
obtain ⟨m, hmW, hmV⟩ := (hWpos.and hsmall).exists
exact ⟨squareDimension m, f m, (hf m).1, (hf m).2, hmW, hmV.le⟩
def divisorMultiplicity (k n : ℕ) : ℕ := (ArithmeticFunction.zeta ^ k) n
theorem divisorMultiplicity_one (k : ℕ) : divisorMultiplicity k 1 = 1 := by
exact (ArithmeticFunction.isMultiplicative_zeta.pow).1
theorem divisorMultiplicity_succ (k n : ℕ) :
divisorMultiplicity (k+1) n = ∑ d ∈ n.divisors, divisorMultiplicity k d := by
simp only [divisorMultiplicity, pow_succ, ArithmeticFunction.mul_zeta_apply]
theorem divisorMultiplicity_prime (k : ℕ) {p : ℕ} (hp : Nat.Prime p) :
divisorMultiplicity k p = k := by
induction k with
| zero => simp [divisorMultiplicity, hp.ne_one]
| succ k ih =>
rw [divisorMultiplicity_succ, hp.divisors]
simp [hp.ne_one.symm, divisorMultiplicity_one, ih, Nat.add_comm]
theorem divisorMultiplicity_squarefree (k : ℕ) {q : ℕ} (hq : Squarefree q) :
divisorMultiplicity k q = k ^ q.primeFactors.card := by
rw [divisorMultiplicity, ← ArithmeticFunction.IsMultiplicative.prod_primeFactors
(ArithmeticFunction.isMultiplicative_zeta.pow) hq]
calc
_ = ∏ p ∈ q.primeFactors, k := Finset.prod_congr rfl fun p hp =>
divisorMultiplicity_prime k (Nat.prime_of_mem_primeFactors hp)
_ = _ := by simp
theorem reciprocal_divisor_sum_le (f : ℕ → ℝ) (hf : ∀ n, 0 ≤ f n) (Q : ℕ) :
(∑ q ∈ Finset.Icc 1 Q, (∑ d ∈ q.divisors, f d) / (q : ℝ)) ≤
(∑ d ∈ Finset.Icc 1 Q, f d / (d : ℝ)) * (harmonic Q : ℝ) := by
classical
let s := (Finset.Icc 1 Q).sigma fun q => q.divisors
let t := (Finset.Icc 1 Q) ×ˢ (Finset.Icc 1 Q)
let e : (a : ℕ) × ℕ → ℕ × ℕ := fun x => (x.2, x.1/x.2)
have he_mem : ∀ x ∈ s, e x ∈ t := by
rintro ⟨q,d⟩ hx
obtain ⟨hq, hd⟩ := Finset.mem_sigma.mp hx
obtain ⟨hq1,hqQ⟩ := Finset.mem_Icc.mp hq
obtain ⟨hdq,hq0⟩ := Nat.mem_divisors.mp hd
have hd0 : 0 < d := Nat.pos_of_dvd_of_pos hdq hq1
have hdle : d ≤ q := Nat.le_of_dvd hq1 hdq
have hdivpos : 0 < q/d := Nat.div_pos hdle hd0
exact Finset.mem_product.mpr ⟨Finset.mem_Icc.mpr ⟨hd0, hdle.trans hqQ⟩,
Finset.mem_Icc.mpr ⟨hdivpos, (Nat.div_le_self q d).trans hqQ⟩⟩
have he_inj : Set.InjOn e s := by
rintro ⟨q,d⟩ hx ⟨q',d'⟩ hy he
obtain ⟨hq,hd⟩ := Finset.mem_sigma.mp hx
obtain ⟨hq',hd'⟩ := Finset.mem_sigma.mp hy
have hed : d = d' := congrArg Prod.fst he
have heq : q/d = q'/d' := congrArg Prod.snd he
have hdq : d ∣ q := (Nat.mem_divisors.mp hd).1
have hdq' : d' ∣ q' := (Nat.mem_divisors.mp hd').1
have hqq : q = q' := by
rw [← Nat.div_mul_cancel hdq, ← Nat.div_mul_cancel hdq', heq, hed]
subst d'
subst q'
rfl
have hsum : (∑ q ∈ Finset.Icc 1 Q, (∑ d ∈ q.divisors, f d) / (q : ℝ)) =
∑ x ∈ s, f (e x).1 / (e x).1 / (e x).2 := by
dsimp only [s]
rw [Finset.sum_sigma]
apply Finset.sum_congr rfl
intro q hq
rw [Finset.sum_div]
apply Finset.sum_congr rfl
intro d hd
have hdq := (Nat.mem_divisors.mp hd).1
dsimp only [e]
rw [div_div, ← Nat.cast_mul, Nat.mul_div_cancel' hdq]
rw [hsum]
calc
_ = ∑ x ∈ s.image e, f x.1 / (x.1 : ℝ) / (x.2 : ℝ) := by
rw [Finset.sum_image he_inj]
_ ≤ ∑ x ∈ t, f x.1 / (x.1 : ℝ) / (x.2 : ℝ) :=
Finset.sum_le_sum_of_subset_of_nonneg (Finset.image_subset_iff.mpr he_mem)
(fun x _ _ => div_nonneg (div_nonneg (hf _) (Nat.cast_nonneg _)) (Nat.cast_nonneg _))
_ = _ := by
simp only [t, Finset.sum_product, div_eq_mul_inv, Finset.sum_mul, Finset.mul_sum,
harmonic_eq_sum_Icc, Rat.cast_sum, Rat.cast_inv, Rat.cast_natCast]
rw [Finset.sum_comm]
theorem sum_divisorMultiplicity_reciprocal_le (k Q : ℕ) :
(∑ q ∈ Finset.Icc 1 Q, (divisorMultiplicity k q : ℝ) / (q : ℝ)) ≤
(harmonic Q : ℝ) ^ k := by
induction k with
| zero =>
by_cases hQ : Q = 0
· subst Q; simp
· have hQ1 : 1 ≤ Q := Nat.one_le_iff_ne_zero.mpr hQ
simp [divisorMultiplicity, ArithmeticFunction.one_apply, ite_div, hQ1]
| succ k ih =>
have h := reciprocal_divisor_sum_le (fun n => (divisorMultiplicity k n : ℝ))
(fun n => Nat.cast_nonneg _) Q
simp only [divisorMultiplicity_succ, Nat.cast_sum] at ⊢
apply h.trans
rw [pow_succ]
exact mul_le_mul_of_nonneg_right ih (by
simp only [harmonic_eq_sum_Icc, Rat.cast_sum, Rat.cast_inv, Rat.cast_natCast]
exact Finset.sum_nonneg fun _ _ => inv_nonneg.mpr (Nat.cast_nonneg _))
theorem squarefree_reciprocal_weight_bound (T Q : ℕ) :
(∑ q ∈ Finset.Icc 1 Q, if Squarefree q then (T : ℝ)^q.primeFactors.card / q else 0) ≤
(harmonic Q : ℝ)^T := by
classical
apply (Finset.sum_le_sum (g := fun q => (divisorMultiplicity T q : ℝ)/(q:ℝ)) ?_).trans
(sum_divisorMultiplicity_reciprocal_le T Q)
intro q _
split_ifs with hq
· rw [divisorMultiplicity_squarefree T hq, Nat.cast_pow]
· positivity
theorem squarefree_totient_lower {q : ℕ} (hq : Squarefree q) :
q ≤ 2 ^ q.primeFactors.card * q.totient := by
rw [Nat.totient_eq_div_primeFactors_mul, Nat.prod_primeFactors_of_squarefree hq,
Nat.div_self (Nat.pos_of_ne_zero hq.ne_zero), one_mul]
calc
q = ∏ p ∈ q.primeFactors, p := (Nat.prod_primeFactors_of_squarefree hq).symm
_ ≤ ∏ p ∈ q.primeFactors, 2 * (p-1) := by
apply Finset.prod_le_prod
intro p hp
have := (Nat.prime_of_mem_primeFactors hp).two_le
omega
_ = _ := by rw [Finset.prod_mul_distrib, Finset.prod_const]
theorem weighted_error_square_bound (K Q : ℕ) (E : ℕ → ℝ) (hE : ∀ q, 0 ≤ E q)
{X L : ℝ} (hX : 0 ≤ X) (hL : 0 ≤ L)
(hb : ∀ q ∈ Finset.Icc 1 Q, Squarefree q →
E q ≤ X/(q:ℝ) * (L + 2^q.primeFactors.card)) :
(∑ q ∈ Finset.Icc 1 Q, if Squarefree q then (K:ℝ)^q.primeFactors.card * E q else 0)^2 ≤
(∑ q ∈ Finset.Icc 1 Q, E q) * X *
(L * (harmonic Q : ℝ)^(K^2) + (harmonic Q : ℝ)^(2*K^2)) := by
classical
let s := Finset.Icc 1 Q
let w : ℕ → ℝ := fun q => if Squarefree q then (K:ℝ)^q.primeFactors.card else 0
have hcs := Finset.sum_mul_sq_le_sq_mul_sq s (fun q => Real.sqrt (E q))
(fun q => w q * Real.sqrt (E q))
have heq1 : ∀ q, Real.sqrt (E q) * (w q * Real.sqrt (E q)) = w q * E q := by
intro q
calc
_ = w q * (Real.sqrt (E q))^2 := by ring
_ = _ := by rw [Real.sq_sqrt (hE q)]
simp only [heq1, mul_pow, Real.sq_sqrt (hE _)] at hcs
have hsecond : (∑ q ∈ s, w q ^ 2 * E q) ≤
X * (L * (harmonic Q : ℝ)^(K^2) + (harmonic Q : ℝ)^(2*K^2)) := by
have hterm : ∀ q ∈ s, w q^2 * E q ≤
X * (L * (if Squarefree q then ((K^2:ℕ):ℝ)^q.primeFactors.card / q else 0) +
(if Squarefree q then ((2*K^2:ℕ):ℝ)^q.primeFactors.card / q else 0)) := by
intro q hq
have hqR : (0 : ℝ) < q := by exact_mod_cast (Finset.mem_Icc.mp hq).1
by_cases hsq : Squarefree q
· simp only [w, ite_eq_left hsq]
calc
_ ≤ ((K:ℝ)^q.primeFactors.card)^2 * (X/(q:ℝ) * (L+2^q.primeFactors.card)) :=
mul_le_mul_of_nonneg_left (hb q hq hsq) (sq_nonneg _)
_ = _ := by
rw [Nat.cast_mul, Nat.cast_ofNat, Nat.cast_pow, mul_pow, ← pow_mul, Nat.mul_comm,
pow_mul]
ring
· simp [w, hsq]
calc
_ ≤ ∑ q ∈ s, X * (L *
(if Squarefree q then ((K^2:ℕ):ℝ)^q.primeFactors.card / q else 0) +
(if Squarefree q then ((2*K^2:ℕ):ℝ)^q.primeFactors.card / q else 0)) :=
Finset.sum_le_sum hterm
_ = X * (L * (∑ q ∈ s, if Squarefree q then ((K^2:ℕ):ℝ)^q.primeFactors.card/q else 0) +
∑ q ∈ s, if Squarefree q then ((2*K^2:ℕ):ℝ)^q.primeFactors.card/q else 0) := by
simp only [Finset.mul_sum, Finset.sum_add_distrib, mul_add]
_ ≤ _ := mul_le_mul_of_nonneg_left
(add_le_add (mul_le_mul_of_nonneg_left (squarefree_reciprocal_weight_bound (K^2) Q) hL)
(squarefree_reciprocal_weight_bound (2*K^2) Q)) hX
have hsumE : 0 ≤ ∑ q ∈ s, E q := Finset.sum_nonneg fun q _ => hE q
have h := hcs.trans (mul_le_mul_of_nonneg_left hsecond hsumE)
simp only [w, ite_mul, zero_mul] at h
simpa only [mul_assoc] using h
theorem markedClassError_trivial {X H q a c : ℕ} (hX : 1 ≤ X) (hq : 0 < q)
(hqX : q ≤ X) (ha : a ≤ H) (hc : c < q) (hsq : Squarefree q) :
|(∑ m ∈ residueStarts X q c, theta (m+a)) - (X:ℝ)/q.totient| ≤
(X:ℝ)/(q:ℝ) * (3 * Real.log (2*X+H) + 2^q.primeFactors.card) := by
have hqR : (0:ℝ) < q := by exact_mod_cast hq
have hphi : (0:ℝ) < q.totient := by exact_mod_cast Nat.totient_pos.mpr hq
have hXq : (1:ℝ) ≤ (X:ℝ)/q := (le_div_iff₀ hqR).mpr (by simpa using (show (q:ℝ) ≤ X by exact_mod_cast hqX))
have hboundpos : (1:ℝ) ≤ 2*X+H := by exact_mod_cast (show 1 ≤ 2*X+H by omega)
have hlog : 0 ≤ Real.log (2*X+H) := Real.log_nonneg hboundpos
have htheta : ∀ m ∈ residueStarts X q c, theta (m+a) ≤ Real.log (2*X+H) := by
intro m hm
have hmhi := (Finset.mem_Ioc.mp (Finset.mem_filter.mp hm).1).2
by_cases hp : Nat.Prime (m+a)
· rw [theta, ite_eq_left hp]
exact Real.log_le_log (by exact_mod_cast hp.pos) (by exact_mod_cast (show m+a ≤ 2*X+H by omega))
· simpa [theta, hp]
have hsum : (∑ m ∈ residueStarts X q c, theta (m+a)) ≤
3 * ((X:ℝ)/q) * Real.log (2*X+H) := by
calc
_ ≤ ∑ m ∈ residueStarts X q c, Real.log (2*X+H) := Finset.sum_le_sum htheta
_ = ((residueStarts X q c).card:ℝ) * Real.log (2*X+H) := by simp
_ ≤ ((X:ℝ)/q+2) * Real.log (2*X+H) := by
apply mul_le_mul_of_nonneg_right _ hlog
have hh := (abs_le.mp (residueStarts_card_error X hq hc)).2
linarith
_ ≤ _ := mul_le_mul_of_nonneg_right (by linarith) hlog
have htot : (X:ℝ)/q.totient ≤ (X:ℝ)/q * (2:ℝ)^q.primeFactors.card := by
have ht : (q:ℝ) ≤ (2:ℝ)^q.primeFactors.card * q.totient := by
exact_mod_cast squarefree_totient_lower hsq
apply (div_le_iff₀ hphi).mpr
have hx := mul_le_mul_of_nonneg_left ht (show 0 ≤ (X:ℝ)/q by positivity)
field_simp at hx ⊢
nlinarith
calc
_ ≤ (∑ m ∈ residueStarts X q c, theta (m+a)) + (X:ℝ)/q.totient := by
have hs0 : 0 ≤ ∑ m ∈ residueStarts X q c, theta (m+a) :=
Finset.sum_nonneg fun m _ => theta_nonneg (m+a)
have ht0 : 0 ≤ (X:ℝ)/q.totient := by positivity
exact abs_sub_le_iff.mpr ⟨by linarith, by linarith⟩
_ ≤ 3 * ((X:ℝ)/q) * Real.log (2*X+H) + (X:ℝ)/q * 2^q.primeFactors.card :=
add_le_add hsum htot
_ = _ := by ring
theorem markedError_trivial {X H q : ℕ} (hX : 1 ≤ X) (hq : 0 < q)
(hqX : q ≤ X) (hsq : Squarefree q) :
(markedError X H q : ℝ) ≤
(X:ℝ)/(q:ℝ) * (3 * Real.log (2*X+H) + 2^q.primeFactors.card) := by
have hnonneg : 0 ≤ (X:ℝ)/(q:ℝ) *
(3 * Real.log (2*X+H) + 2^q.primeFactors.card) := by
have : 0 ≤ Real.log (2*X+H) := Real.log_nonneg (by
exact_mod_cast (show 1 ≤ 2*X+H by omega))
positivity
change markedError X H q ≤ NNReal.mk _ hnonneg
apply Finset.sup_le
rintro ⟨a,c⟩ hac
have ha : a ≤ H := by simpa using (Finset.mem_product.mp hac).1
have hc : c < q := Finset.mem_range.mp (Finset.mem_product.mp hac).2
dsimp only
split_ifs
· exact markedClassError_trivial hX hq hqX ha hc hsq
· exact zero_le
noncomputable def residueSlice (f : ℕ → ℝ) (L U q c : ℕ) : ℝ :=
∑ n ∈ (Finset.Ioc L U).filter (fun n => n % q = c), f n
noncomputable def residuePrefix (f : ℕ → ℝ) (Y q c : ℕ) : ℝ :=
residueSlice f 0 Y q c
theorem residuePrefix_sub (f : ℕ → ℝ) {L U : ℕ} (hLU : L ≤ U) (q c : ℕ) :
residuePrefix f U q c - residuePrefix f L q c = residueSlice f L U q c := by
classical
have hunion : Finset.Ioc 0 U = Finset.Ioc 0 L ∪ Finset.Ioc L U := by
ext n
simp only [Finset.mem_Ioc, Finset.mem_union]
omega
have hd : Disjoint ((Finset.Ioc 0 L).filter fun n => n % q = c)
((Finset.Ioc L U).filter fun n => n % q = c) := by
apply Finset.disjoint_left.mpr
intro n hn hm
have hl := (Finset.mem_Ioc.mp (Finset.mem_filter.mp hn).1).2
have hu := (Finset.mem_Ioc.mp (Finset.mem_filter.mp hm).1).1
omega
simp only [residuePrefix, residueSlice, hunion, Finset.filter_union, Finset.sum_union hd]
ring
theorem shifted_sum_eq_residueSlice (f : ℕ → ℝ) (X q a : ℕ) {c : ℕ} (hc : c < q) :
(∑ m ∈ residueStarts X q c, f (m+a)) =
residueSlice f (X+a) (2*X+a) q ((c+a)%q) := by
classical
apply Finset.sum_bij (fun m _ => m+a)
· intro m hm
obtain ⟨hm,hmc⟩ := Finset.mem_filter.mp hm
obtain ⟨hmlo,hmhi⟩ := Finset.mem_Ioc.mp hm
apply Finset.mem_filter.mpr
refine ⟨Finset.mem_Ioc.mpr ⟨by omega, by omega⟩, ?_⟩
have hh : Nat.ModEq q m c := by
change m % q = c % q
rw [hmc, Nat.mod_eq_of_lt hc]
exact hh.add_right a
· intro m _ n _ heq
omega
· intro n hn
obtain ⟨hn,hnc⟩ := Finset.mem_filter.mp hn
obtain ⟨hnlo,hnhi⟩ := Finset.mem_Ioc.mp hn
have ha : a ≤ n := by omega
refine ⟨n-a, Finset.mem_filter.mpr ⟨Finset.mem_Ioc.mpr ⟨by omega, by omega⟩, ?_⟩,
Nat.sub_add_cancel ha⟩
have hh : Nat.ModEq q ((n-a)+a) (c+a) := by
change ((n-a)+a) % q = (c+a) % q
simpa only [Nat.sub_add_cancel ha] using hnc
have hhc := Nat.ModEq.add_right_cancel' a hh
simpa only [Nat.ModEq, Nat.mod_eq_of_lt hc] using hhc
· intro m _
rfl
end LargePrimeGaps
end OAI