roseking's picture
Add lean source and binary files (part 115)
b797a5b verified
Raw History Blame Contribute Delete
17.3 kB
import OAI.NumberTheory.PrimeGaps.CharacterErrors
namespace OAI
namespace LargePrimeGaps
open Filter
open Set Filter MeasureTheory
open scoped Topology ContDiff
open Asymptotics
open Asymptotics
open Asymptotics
open scoped Classical
open scoped ContDiff
open Topology
open scoped Convolution ContDiff Pointwise
open scoped ComplexConjugate
theorem symmetric_kernel_quadratic_le {ι : Type*} (s : Finset ι) (a : ι→ℝ)
(w : ι→ι→ℝ) (hw : ∀ i∈s,∀ j∈s,0≤w i j)
(hs : ∀ i∈s,∀ j∈s,w i j=w j i) :
(∑ i∈s,∑ j∈s,a i*a j*w i j)≤∑ i∈s,a i^2*(∑ j∈s,w i j) := by
have hh : (∑ i∈s,∑ j∈s,a i*a j*w i j)≤
∑ i∈s,∑ j∈s,(a i^2*w i j+a j^2*w i j)/2 := by
apply Finset.sum_le_sum
intro i hi
apply Finset.sum_le_sum
intro j hj
have h := mul_nonneg (sq_nonneg (a i-a j)) (hw i hi j hj)
nlinarith
have hswap : (∑ i∈s,∑ j∈s,a j^2*w i j)=(∑ i∈s,∑ j∈s,a i^2*w i j) := by
rw [Finset.sum_comm]
apply Finset.sum_congr rfl
intro i hi
apply Finset.sum_congr rfl
intro j hj
rw [hs j hj i hi]
calc
_ ≤ _ := hh
_ = _ := by
simp_rw [←Finset.sum_div,Finset.sum_add_distrib]
rw [hswap]
simp only [Finset.mul_sum]
ring
theorem norm_sum_smul_sq_le_gram {ι E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℂ E]
(s : Finset ι) (v : ι→E) (c : ι→ℂ) :
‖∑ i∈s,c i • v i‖^2≤∑ i∈s,‖c i‖^2*(∑ j∈s,‖inner ℂ (v i) (v j)‖) := by
calc
_ = ∑ i∈s,∑ j∈s,(conj (c i)*(c j*inner ℂ (v i) (v j))).re := by
rw [InnerProductSpace.norm_sq_eq_re_inner (𝕜:=ℂ)]
simp only [sum_inner,inner_sum,inner_smul_left,inner_smul_right,Finset.mul_sum,map_sum]
rw [Finset.sum_comm]
apply Finset.sum_congr rfl
intro i _
apply Finset.sum_congr rfl
intro j _
change (c j * (conj (c i) * inner ℂ (v i) (v j))).re = _
congr 1
ring
_ ≤ ∑ i∈s,∑ j∈s,‖c i‖*‖c j‖*‖inner ℂ (v i) (v j)‖ := by
apply Finset.sum_le_sum
intro i _
apply Finset.sum_le_sum
intro j _
simpa only [norm_mul,Complex.norm_conj,mul_assoc] using
Complex.re_le_norm (conj (c i)*(c j*inner ℂ (v i) (v j)))
_ ≤ _ := symmetric_kernel_quadratic_le s (fun i => ‖c i‖)
(fun i j => ‖inner ℂ (v i) (v j)‖) (fun _ _ _ _ => norm_nonneg _)
(fun i _ j _ => by rw [←inner_conj_symm,Complex.norm_conj])
theorem gram_large_sieve {ι E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℂ E]
(s : Finset ι) (v : ι→E) {B : ℝ} (hB : 0≤B)
(hrows : ∀ i∈s,(∑ j∈s,‖inner ℂ (v i) (v j)‖)≤B) (x : E) :
(∑ i∈s,‖inner ℂ (v i) x‖^2)≤B*‖x‖^2 := by
let c : ι→ℂ := fun i => inner ℂ (v i) x
let y : E := ∑ i∈s,c i • v i
let A : ℝ := ∑ i∈s,‖c i‖^2
have hA : 0≤A := Finset.sum_nonneg (fun _ _ => sq_nonneg _)
have hy : ‖y‖^2≤B*A := by
apply (norm_sum_smul_sq_le_gram s v c).trans
calc
_ ≤ ∑ i∈s,‖c i‖^2*B := Finset.sum_le_sum
(fun i hi => mul_le_mul_of_nonneg_left (hrows i hi) (sq_nonneg _))
_ = B*A := by rw [←Finset.sum_mul,mul_comm]
have hxy : inner ℂ x y=(A:ℂ) := by
simp only [y,inner_sum,inner_smul_right,A,Complex.ofReal_sum]
apply Finset.sum_congr rfl
intro i _
change inner ℂ (v i) x * inner ℂ x (v i)=_
rw [←inner_conj_symm x (v i)]
simpa only [Complex.normSq_eq_norm_sq,c] using Complex.mul_conj (inner ℂ (v i) x)
have hn := norm_inner_le_norm (𝕜:=ℂ) x y
rw [hxy,Complex.norm_real,Real.norm_eq_abs,abs_of_nonneg hA] at hn
have hn2 : A^2≤‖x‖^2*‖y‖^2 := by
nlinarith [norm_nonneg x,norm_nonneg y]
have hprod := mul_le_mul_of_nonneg_left hy (sq_nonneg ‖x‖)
change A≤B*‖x‖^2
by_cases hA0 : A=0
· rw [hA0]
exact mul_nonneg hB (sq_nonneg _)
· apply le_of_mul_le_mul_right (a := A) ?_ (lt_of_le_of_ne hA (Ne.symm hA0))
calc
A*A = A^2 := by ring
_ ≤ _ := hn2.trans hprod
_ = (B*‖x‖^2)*A := by ring
noncomputable def bvExp (x : ℝ) : ℂ := Complex.exp (Complex.I*(2*Real.pi*x:ℝ))
@[simp] theorem bvExp_zero : bvExp 0=1 := by simp [bvExp]
@[simp] theorem norm_bvExp (x : ℝ) : ‖bvExp x‖=1 := by simp [bvExp,Complex.norm_exp]
theorem bvExp_add (x y : ℝ) : bvExp (x+y)=bvExp x*bvExp y := by
unfold bvExp
rw [←Complex.exp_add]
congr 1
push_cast
ring
theorem conj_bvExp (x : ℝ) : conj (bvExp x)=bvExp (-x) := by
unfold bvExp
rw [←Complex.exp_conj]
congr 1
simp only [map_mul, Complex.conj_I, Complex.conj_ofReal]
push_cast
ring
theorem bvExp_nat_mul (n : ℕ) (x : ℝ) : bvExp ((n:ℝ)*x)=bvExp x^n := by
unfold bvExp
rw [←Complex.exp_nat_mul]
congr 1
push_cast
ring
theorem bvExp_sub_one_lower {x : ℝ} (hx : |x|≤1/2) :
4*|x|≤‖bvExp x-1‖ := by
rw [bvExp,Complex.norm_exp_I_mul_ofReal_sub_one]
have hs : |Real.pi*x|≤Real.pi/2 := by
rw [abs_mul,abs_of_pos Real.pi_pos]
nlinarith [Real.pi_pos]
have h := Real.mul_abs_le_abs_sin hs
rw [abs_mul,abs_of_pos Real.pi_pos] at h
have hpi : Real.pi≠0 := ne_of_gt Real.pi_pos
have he : 2/Real.pi*(Real.pi*|x|)=2*|x| := by field_simp
rw [he] at h
have hid : 2*Real.pi*x/2=Real.pi*x := by ring
rw [hid,Real.norm_eq_abs,abs_mul,abs_of_pos (by norm_num : (0:ℝ)<2)]
linarith
theorem exponential_sum_bound (N : ℕ) {x : ℝ} (hx : |x|≤1/2) (hx0 : x≠0) :
‖∑ n∈Finset.range N,bvExp ((n:ℝ)*x)‖≤1/(2*|x|) := by
have ha : 0 < |x| := abs_pos.mpr hx0
have hden := bvExp_sub_one_lower hx
have hn : 0<‖bvExp x-1‖ := lt_of_lt_of_le (by positivity : 0<4*|x|) hden
have he := geom_sum_mul (bvExp x) N
have hnorm := congrArg norm he
rw [norm_mul] at hnorm
have hu : ‖bvExp x^N-1‖≤2 := by
calc
_ ≤ ‖bvExp x^N‖+‖(1:ℂ)‖ := norm_sub_le _ _
_ = 2 := by simp [norm_pow]; norm_num
have htimes : ‖∑ n∈Finset.range N,bvExp x^n‖*(4*|x|)≤2 := by
exact (mul_le_mul_of_nonneg_left hden (norm_nonneg _)).trans (hnorm.trans_le hu)
simp_rw [bvExp_nat_mul]
apply (le_div_iff₀ (by positivity : (0:ℝ)<2*|x|)).mpr
nlinarith
theorem reciprocal_sum_le_harmonic {ι : Type*} (s : Finset ι) (t : ι→ℝ) (D : ℕ)
(ht : ∀ i∈s,1≤t i ∧ t i≤D)
(hsep : ∀ i∈s,∀ j∈s,i≠j→1≤|t i-t j|) :
(∑ i∈s,1/t i)≤(harmonic D:ℝ) := by
classical
let r : ι→ℕ := fun i => ⌊t i⌋₊
have hr : ∀ i∈s,r i∈Finset.Icc 1 D := by
intro i hi
exact Finset.mem_Icc.mpr ⟨Nat.le_floor (by simpa using (ht i hi).1),
Nat.floor_le_of_le (ht i hi).2⟩
have hinj : Set.InjOn r s := by
intro i hi j hj he
by_contra hij
have h := hsep i hi j hj hij
have hil := Nat.floor_le (le_trans (by norm_num : (0:ℝ)≤1) (ht i hi).1)
have hjl := Nat.floor_le (le_trans (by norm_num : (0:ℝ)≤1) (ht j hj).1)
have hiu := Nat.lt_floor_add_one (t i)
have hju := Nat.lt_floor_add_one (t j)
change ⌊t i⌋₊=⌊t j⌋₊ at he
rw [he] at hil hiu
rcases le_abs.mp h with h|h <;> linarith
calc
_ ≤ ∑ i∈s,1/(r i:ℝ) := by
apply Finset.sum_le_sum
intro i hi
apply one_div_le_one_div_of_le
· exact_mod_cast (Finset.mem_Icc.mp (hr i hi)).1
· exact Nat.floor_le (le_trans (by norm_num : (0:ℝ)≤1) (ht i hi).1)
_ = ∑ k∈s.image r,1/(k:ℝ) := (Finset.sum_image (f := fun k : ℕ => (1:ℝ)/k) hinj).symm
_ ≤ ∑ k∈Finset.Icc 1 D,1/(k:ℝ) :=
Finset.sum_le_sum_of_subset_of_nonneg (Finset.image_subset_iff.mpr hr)
(fun _ _ _ => by positivity)
_ = _ := by simp [harmonic_eq_sum_Icc]
theorem reciprocal_sum_le_scaled_harmonic {ι : Type*} (s : Finset ι) (t : ι→ℝ)
{D : ℕ} (hD : 0<D) (ht : ∀ i∈s,1/(D:ℝ)≤t i ∧ t i≤1)
(hsep : ∀ i∈s,∀ j∈s,i≠j→1/(D:ℝ)≤|t i-t j|) :
(∑ i∈s,1/t i)≤(D:ℝ)*(harmonic D:ℝ) := by
have hDr : 0<(D:ℝ) := by exact_mod_cast hD
have hh := reciprocal_sum_le_harmonic s (fun i => (D:ℝ)*t i) D
(fun i hi => ⟨by have h := mul_le_mul_of_nonneg_left (ht i hi).1 hDr.le
field_simp at h
nlinarith,
by nlinarith [(ht i hi).2]⟩)
(fun i hi j hj hij => by
rw [←mul_sub,abs_mul,abs_of_pos hDr]
have h := (div_le_iff₀ hDr).mp (hsep i hi j hj hij)
nlinarith)
have hm := mul_le_mul_of_nonneg_left hh hDr.le
rw [Finset.mul_sum] at hm
calc
_ = ∑ i∈s,(D:ℝ)*(1/((D:ℝ)*t i)) := by
apply Finset.sum_congr rfl
intro i _
field_simp
_ ≤ _ := hm
@[simp] theorem bvExp_int (m : ℤ) : bvExp m=1 := by
unfold bvExp
have he : Complex.I * ((2*Real.pi*(m:ℝ):ℝ):ℂ)=(m:ℂ)*(2*Real.pi*Complex.I) := by
push_cast
ring
rw [he,Complex.exp_int_mul,Complex.exp_two_pi_mul_I,one_zpow]
theorem bvExp_sub_int (x : ℝ) (m : ℤ) : bvExp (x-m)=bvExp x := by
rw [sub_eq_add_neg,bvExp_add]
have h : bvExp (-(m:ℝ))=1 := by simpa using bvExp_int (-m)
rw [h,mul_one]
noncomputable def bvCentered (x : ℝ) : ℝ := x-(⌊x+1/2⌋:ℤ)
theorem abs_bvCentered_le (x : ℝ) : |bvCentered x|≤1/2 := by
have hl := Int.floor_le (x+1/2)
have hu := Int.lt_floor_add_one (x+1/2)
dsimp [bvCentered]
exact abs_le.mpr ⟨by linarith,by linarith⟩
theorem bvExp_centered (x : ℝ) : bvExp (bvCentered x)=bvExp x := bvExp_sub_int _ _
theorem exponential_sum_centered (N : ℕ) (x : ℝ) :
(∑ n∈Finset.range N,bvExp ((n:ℝ)*bvCentered x))=
∑ n∈Finset.range N,bvExp ((n:ℝ)*x) := by
simp_rw [bvExp_nat_mul,bvExp_centered]
theorem centered_difference_separated {ι : Type*} (s : Finset ι) (θ : ι→ℝ) {D : ℕ}
(hsep : ∀ i∈s,∀ j∈s,i≠j→∀ m:ℤ,1/(D:ℝ)≤|θ i-θ j-m|)
(a : ℝ) {i j : ι} (hi : i∈s) (hj : j∈s) (hij : i≠j) :
1/(D:ℝ)≤|bvCentered (θ i-a)-bvCentered (θ j-a)| := by
have h := hsep i hi j hj hij (⌊θ i-a+1/2⌋-⌊θ j-a+1/2⌋)
dsimp [bvCentered]
convert h using 2
push_cast
ring
theorem exponential_kernel_row_bound {ι : Type*} (s : Finset ι) (θ : ι→ℝ)
{D : ℕ} (hD : 0<D)
(hsep : ∀ i∈s,∀ j∈s,i≠j→∀ m:ℤ,1/(D:ℝ)≤|θ i-θ j-m|)
(N : ℕ) {i : ι} (hi : i∈s) :
(∑ j∈s,‖∑ n∈Finset.range N,bvExp ((n:ℝ)*(θ j-θ i))‖)≤
(N:ℝ)+(D:ℝ)*(harmonic D:ℝ) := by
classical
let t := s.erase i
let r := fun j => bvCentered (θ j-θ i)
have hDr : 0<(D:ℝ) := by exact_mod_cast hD
have hr : ∀ j∈t,1/(D:ℝ)≤|r j| := by
intro j hj
rcases Finset.mem_erase.mp hj with ⟨hji,hjs⟩
exact hsep j hjs i hi hji ⌊θ j-θ i+1/2⌋
have hn : ∀ j∈t,r j≠0 := by
intro j hj hj0
have h := hr j hj
rw [hj0,abs_zero] at h
exact (not_le_of_gt (one_div_pos.mpr hDr)) h
have hpair : ∀ j∈t,∀ k∈t,j≠k→1/(D:ℝ)≤|r j-r k| := by
intro j hj k hk hjk
exact centered_difference_separated s θ hsep (θ i)
(Finset.mem_of_mem_erase hj) (Finset.mem_of_mem_erase hk) hjk
have hhalf : ∀ b:Bool,
(∑ j∈t.filter (fun j => decide (0≤r j)=b),1/|r j|)≤(D:ℝ)*(harmonic D:ℝ) := by
intro b
apply reciprocal_sum_le_scaled_harmonic _ _ hD
· intro j hj
exact ⟨hr j ((Finset.mem_filter.mp hj).1),(abs_bvCentered_le _).trans (by norm_num)⟩
· intro j hj k hk hjk
have h := hpair j ((Finset.mem_filter.mp hj).1) k ((Finset.mem_filter.mp hk).1) hjk
have hjb := (Finset.mem_filter.mp hj).2
have hkb := (Finset.mem_filter.mp hk).2
cases b <;> simp only [decide_eq_false_iff_not,decide_eq_true_eq,not_le] at hjb hkb
· simpa only [abs_of_neg hjb,abs_of_neg hkb,neg_sub_neg,abs_sub_comm] using h
· simpa only [abs_of_nonneg hjb,abs_of_nonneg hkb] using h
have hrec : (∑ j∈t,1/|r j|)≤2*(D:ℝ)*(harmonic D:ℝ) := by
have hp := hhalf true
have hm := hhalf false
simp only [decide_eq_true_eq,decide_eq_false_iff_not] at hp hm
have he := Finset.sum_filter_add_sum_filter_not t (fun j => 0≤r j) (fun j => 1/|r j|)
linarith
have hoff : (∑ j∈t,‖∑ n∈Finset.range N,bvExp ((n:ℝ)*(θ j-θ i))‖)≤
(D:ℝ)*(harmonic D:ℝ) := by
calc
_ ≤ ∑ j∈t,1/(2*|r j|) := by
apply Finset.sum_le_sum
intro j hj
rw [←exponential_sum_centered]
exact exponential_sum_bound N (abs_bvCentered_le _) (hn j hj)
_ = (∑ j∈t,1/|r j|)/2 := by
rw [Finset.sum_div]
apply Finset.sum_congr rfl
intro j _
ring
_ ≤ _ := by linarith
rw [←Finset.sum_erase_add _ _ hi]
have hd : ‖∑ n∈Finset.range N,bvExp ((n:ℝ)*(θ i-θ i))‖=(N:ℝ) := by simp
rw [hd]
linarith
noncomputable def bvExponentialVector (N : ℕ) (θ : ℝ) : EuclideanSpace ℂ (Fin N) :=
WithLp.toLp 2 (fun n => bvExp (-((n:ℕ):ℝ)*θ))
theorem inner_bvExponentialVector (N : ℕ) (θ η : ℝ) :
inner ℂ (bvExponentialVector N θ) (bvExponentialVector N η)=
∑ n∈Finset.range N,bvExp ((n:ℝ)*(θ-η)) := by
simp only [PiLp.inner_apply,RCLike.inner_apply,bvExponentialVector]
simp_rw [mul_comm (bvExp _)]
simp_rw [conj_bvExp,←bvExp_add]
have he : ∀ n:Fin N,-(-((n:ℕ):ℝ)*θ)+(-((n:ℕ):ℝ)*η)=((n:ℕ):ℝ)*(θ-η) := by
intro n
ring
simp_rw [he]
exact Fin.sum_univ_eq_sum_range (fun n : ℕ => bvExp ((n:ℝ)*(θ-η))) N
theorem inner_bvExponentialVector_coefficients (N : ℕ) (θ : ℝ) (a : Fin N→ℂ) :
inner ℂ (bvExponentialVector N θ) (WithLp.toLp 2 a)=
∑ n:Fin N,a n*bvExp (((n:ℕ):ℝ)*θ) := by
simp only [PiLp.inner_apply,RCLike.inner_apply,bvExponentialVector]
apply Finset.sum_congr rfl
intro n _
rw [conj_bvExp]
congr 2
ring
theorem additive_large_sieve {ι : Type*} (s : Finset ι) (θ : ι→ℝ)
{D : ℕ} (hD : 0<D)
(hsep : ∀ i∈s,∀ j∈s,i≠j→∀ m:ℤ,1/(D:ℝ)≤|θ i-θ j-m|)
(N : ℕ) (a : Fin N→ℂ) :
(∑ i∈s,‖∑ n:Fin N,a n*bvExp (((n:ℕ):ℝ)*θ i)‖^2)≤
((N:ℝ)+(D:ℝ)*(harmonic D:ℝ))*(∑ n:Fin N,‖a n‖^2) := by
have hH : 0≤(harmonic D:ℝ) := by
rw [harmonic_eq_sum_Icc,Rat.cast_sum]
exact Finset.sum_nonneg (fun _ _ => by simp only [Rat.cast_inv,Rat.cast_natCast]; positivity)
have hB : 0≤(N:ℝ)+(D:ℝ)*(harmonic D:ℝ) := by positivity
have hr : ∀ i∈s,(∑ j∈s,‖inner ℂ (bvExponentialVector N (θ i))
(bvExponentialVector N (θ j))‖)≤(N:ℝ)+(D:ℝ)*(harmonic D:ℝ) := by
intro i hi
simp_rw [inner_bvExponentialVector]
have hh := exponential_kernel_row_bound s (fun i => -θ i) hD
(fun j hj k hk hjk m => by
have h := hsep j hj k hk hjk (-m)
have he : -θ j- -θ k-(m:ℝ)=-(θ j-θ k-(-m:ℤ)) := by
push_cast
ring
rw [he,abs_neg]
exact h) N hi
convert hh using 1
apply Finset.sum_congr rfl
intro j _
congr 1
apply Finset.sum_congr rfl
intro n _
congr 1
ring
have h := gram_large_sieve s (fun i => bvExponentialVector N (θ i)) hB hr (WithLp.toLp 2 a)
simpa only [inner_bvExponentialVector_coefficients,EuclideanSpace.norm_sq_eq,WithLp.ofLp_toLp] using h
theorem rat_abs_lower (r : ℚ) (hr : r≠0) : 1/(r.den:ℝ)≤|(r:ℝ)| := by
have hn : r.num≠0 := fun h => hr (Rat.zero_of_num_zero h)
have ha : (1:ℝ)≤|(r.num:ℝ)| := by
exact_mod_cast Int.one_le_abs hn
rw [Rat.cast_def,abs_div,abs_of_pos (by exact_mod_cast r.den_pos : (0:ℝ)<r.den)]
exact div_le_div_of_nonneg_right ha (Nat.cast_nonneg _)
theorem rational_frequency_separation {r t : ℚ} {Q : ℕ}
(hr : 0≤r ∧ r<1) (ht : 0≤t ∧ t<1) (hrt : r≠t)
(hrQ : r.den≤Q) (htQ : t.den≤Q) (m : ℤ) :
1/((Q^2:ℕ):ℝ)≤|(r:ℝ)-(t:ℝ)-m| := by
have hu0 : r-t-(m:ℚ)≠0 := by
intro he
have hm0 : m=0 := by
have hlo : (-1:ℚ)<(m:ℚ) := by linarith [hr.1,ht.2]
have hup : (m:ℚ)<1 := by linarith [ht.1,hr.2]
have h1 : (-1:ℤ) < m := by exact_mod_cast hlo
have h2 : m<1 := by exact_mod_cast hup
omega
simp only [hm0,Int.cast_zero,sub_zero,sub_eq_zero] at he
exact hrt he
have hd : (r-t-(m:ℚ)).den≤Q^2 := by
rw [Rat.sub_intCast_den]
calc
_ ≤ r.den*t.den := Nat.le_of_dvd (Nat.mul_pos r.den_pos t.den_pos) (Rat.sub_den_dvd _ _)
_ ≤ Q*Q := Nat.mul_le_mul hrQ htQ
_ = _ := by ring
have hl := rat_abs_lower (r-t-(m:ℚ)) hu0
push_cast at hl
exact (one_div_le_one_div_of_le
(by exact_mod_cast (r-t-(m:ℚ)).den_pos : (0:ℝ)<(r-t-(m:ℚ)).den)
(by exact_mod_cast hd)).trans hl
theorem rational_additive_large_sieve (s : Finset ℚ) {Q : ℕ} (hQ : 0<Q)
(hs : ∀ r∈s,0≤r ∧ r<1 ∧ r.den≤Q) (N : ℕ) (a : Fin N→ℂ) :
(∑ r∈s,‖∑ n:Fin N,a n*bvExp (((n:ℕ):ℝ)*(r:ℝ))‖^2)≤
((N:ℝ)+(Q:ℝ)^2*(harmonic (Q^2):ℝ))*(∑ n:Fin N,‖a n‖^2) := by
have h := additive_large_sieve s (fun r => (r:ℝ)) (pow_pos hQ 2)
(fun r hr t ht hrt m => rational_frequency_separation
⟨(hs r hr).1,(hs r hr).2.1⟩ ⟨(hs t ht).1,(hs t ht).2.1⟩ hrt
(hs r hr).2.2 (hs t ht).2.2 m) N a
simpa only [Nat.cast_pow] using h
end LargePrimeGaps
end OAI