roseking's picture
Add lean source and binary files (part 63)
760f90e verified
Raw History Blame Contribute Delete
17.6 kB
import OAI.Computability.RationalHitting.Generator
namespace OAI
namespace RationalHitting.CyclotomicRing
open Polynomial Matrix Module
noncomputable section
lemma root_degree (e : ℕ) : AdjoinRoot.root (modulus e)^degree e = -1 := by
have h := AdjoinRoot.eval₂_root (modulus e)
change Polynomial.eval₂ (AdjoinRoot.of (modulus e)) (AdjoinRoot.root (modulus e))
((X : ℚ[X])^degree e+1) = 0 at h
rw [Polynomial.eval₂_add,Polynomial.eval₂_pow,Polynomial.eval₂_X,Polynomial.eval₂_one] at h
exact eq_neg_of_add_eq_zero_left h
lemma root_pow_reduce (e k : ℕ) :
AdjoinRoot.root (modulus e)^k = (-1 : R e)^(k/degree e) *
(basis e ⟨k % degree e,Nat.mod_lt _ (degree_pos e)⟩) := by
rw [basis_apply,← root_degree,← pow_mul,← pow_add]
congr 1
change k = degree e*(k/degree e)+k%degree e
exact (Nat.div_add_mod k (degree e)).symm
/-- Every regular-representation entry of a cyclotomic monomial is 0 or ±1.
This also gives an explicit integral computation with a division and remainder. -/
lemma rho_root_pow (e k : ℕ) (i j : Fin (degree e)) :
rho e (AdjoinRoot.root (modulus e)^k) i j =
if (k+j.val) % degree e = i.val then (-1 : ℚ)^((k+j.val)/degree e) else 0 := by
rw [rho,Algebra.leftMulMatrix_eq_repr_mul,basis_apply,← pow_add,root_pow_reduce]
rw [show (-1 : R e)^((k+j.val)/degree e) =
algebraMap ℚ (R e) ((-1 : ℚ)^((k+j.val)/degree e)) by simp]
rw [← Algebra.smul_def, map_smul, Basis.repr_self,Finsupp.smul_apply,Finsupp.single_apply]
simp only [smul_eq_mul,mul_ite,mul_one,mul_zero]
congr 1
exact propext ⟨fun h => congrArg Fin.val h,fun h => Fin.ext h⟩
lemma rho_character (e : ℕ) (a : ZMod (dimension e)) (i j : Fin (degree e)) :
rho e (character e a) i j =
if (a.val+j.val) % degree e = i.val then (-1 : ℚ)^((a.val+j.val)/degree e) else 0 := by
rw [character,AddChar.zmodChar_apply,rho_root_pow]
def signedEntry (e : ℕ) (a : ZMod (dimension e)) (i j : Fin (degree e)) : ℤ :=
if (a.val+j.val) % degree e = i.val then (-1 : ℤ)^((a.val+j.val)/degree e) else 0
lemma rho_character_integral (e : ℕ) (a : ZMod (dimension e)) (i j : Fin (degree e)) :
rho e (character e a) i j = (signedEntry e a i j : ℚ) := by
simp only [rho_character,signedEntry,Int.cast_ite,Int.cast_pow,Int.cast_neg,Int.cast_one,Int.cast_zero]
lemma signedEntry_abs (e : ℕ) (a : ZMod (dimension e)) (i j : Fin (degree e)) :
|signedEntry e a i j| ≤ 1 := by
unfold signedEntry
split_ifs <;> simp [abs_pow]
end
end RationalHitting.CyclotomicRing
namespace RationalHitting.IntegralTest
open Polynomial Matrix
open scoped BigOperators
/-- Integer computation of the exact expanded Taylor-reversal matrix at t. -/
def full (M : ℕ) (a t : ℤ) : Matrix (Fin M) (Fin M) ℤ := fun i j =>
∑ r : Fin M, ((-a)^(r.rev.val-i.val)*(r.rev.val.choose i.val : ℤ)) *
(a^(j.val-r.val)*(j.val.choose r.val : ℤ)) * t^r.val
def padded (M N : ℕ) (a t : ℤ) : Matrix (Fin M) (Fin M) ℤ :=
fun i j => if j.val < N then full M a t i j else 0
lemma coeff_bound (a : ℤ) (w M k j : ℕ) (hw : 1 ≤ w) (ha : |a| ≤ w) (hk : k ≤ M) :
|(((X+C a)^k : ℤ[X]).coeff j)| ≤ (2*w : ℤ)^M := by
rw [coeff_X_add_C_pow,abs_mul,abs_pow,Int.abs_natCast]
have hw' : (1 : ℤ) ≤ w := by exact_mod_cast hw
have hc : (k.choose j : ℤ) ≤ (2 : ℤ)^M := by
exact_mod_cast (Nat.choose_le_two_pow k j).trans (Nat.pow_le_pow_right (by omega) hk)
calc |a|^(k-j)*(k.choose j : ℤ) ≤ (w : ℤ)^M * (2 : ℤ)^M := by
apply mul_le_mul _ hc (by positivity) (by positivity)
exact (pow_le_pow_left₀ (abs_nonneg a) ha (k-j)).trans (pow_le_pow_right₀ hw' (Nat.sub_le k j |>.trans hk))
_ = _ := by rw [← mul_pow]; congr 1; ring
lemma full_bound (M : ℕ) (a t : ℤ) (w H : ℕ) (hw : 1 ≤ w) (hH : 1 ≤ H)
(ha : |a| ≤ w) (ht : |t| ≤ H) (i j : Fin M) :
|full M a t i j| ≤ (M : ℤ)*(2*w : ℤ)^(2*M)*(H : ℤ)^M := by
unfold full
simp_rw [← coeff_X_add_C_pow]
calc |∑ r : Fin M, _| ≤ ∑ r : Fin M, |(((X+C (-a))^r.rev.val : ℤ[X]).coeff i.val) *
(((X+C a)^j.val : ℤ[X]).coeff r.val) * t^r.val| := Finset.abs_sum_le_sum_abs _ _
_ ≤ ∑ _r : Fin M, (2*w : ℤ)^(2*M)*(H : ℤ)^M := by
apply Finset.sum_le_sum
intro r _
rw [abs_mul,abs_mul,abs_pow]
have hh : (1 : ℤ) ≤ H := by exact_mod_cast hH
calc _ ≤ ((2*w : ℤ)^M*(2*w : ℤ)^M)*(H : ℤ)^M := by
apply mul_le_mul _ _ (by positivity) (by positivity)
· apply mul_le_mul (coeff_bound (-a) w M _ _ hw (by simpa using ha) (Nat.le_of_lt r.rev.isLt))
(coeff_bound a w M _ _ hw ha (Nat.le_of_lt j.isLt)) (abs_nonneg _) (by positivity)
· exact (pow_le_pow_left₀ (abs_nonneg t) ht r.val).trans (pow_le_pow_right₀ hh (Nat.le_of_lt r.isLt))
_ = _ := by rw [← pow_add]; simp [two_mul]
_ = _ := by simp [mul_assoc]
lemma padded_bound (M N : ℕ) (a t : ℤ) (w H : ℕ) (hw : 1 ≤ w) (hH : 1 ≤ H)
(ha : |a| ≤ w) (ht : |t| ≤ H) (i j : Fin M) :
|padded M N a t i j| ≤ (M : ℤ)*(2*w : ℤ)^(2*M)*(H : ℤ)^M := by
by_cases h : j.val < N
· simpa [padded,h] using full_bound M a t w H hw hH ha ht i j
· simp only [padded,h,ite_false,abs_zero]; positivity
end RationalHitting.IntegralTest
namespace RationalHitting.IntegralTest
open Matrix Polynomial
open scoped BigOperators
lemma full_cast {K : Type*} [Field K] (M : ℕ) (a t : ℤ) (i j : Fin M) :
Polynomial.eval (t : K) (TestPolynomial.full M (a : K) i j) =
(full M a t i j : K) := by
simp only [TestPolynomial.full,full,coeff_X_add_C_pow,Polynomial.eval_finsetSum,
Polynomial.eval_mul,Polynomial.eval_C,Polynomial.eval_pow,Polynomial.eval_X]
simp only [Int.cast_sum,Int.cast_mul,Int.cast_pow,Int.cast_neg,Int.cast_natCast]
lemma padded_cast {K : Type*} [Field K] (M N : ℕ) (a t : ℤ) (i j : Fin M) :
Polynomial.eval (t : K) (TestPolynomial.padded M N (a : K) i j) =
(padded M N a t i j : K) := by
by_cases h : j.val < N
· simpa [TestPolynomial.padded,padded,h] using full_cast M a t i j (K := K)
· simp [TestPolynomial.padded,padded,h]
end RationalHitting.IntegralTest
namespace RationalHitting.ThreeLift
open Polynomial MvPolynomial Matrix
open scoped BigOperators
noncomputable section
variable {K : Type*} [Field K] {d : ℕ} [NeZero d]
lemma eval_uni (x : Fin 3 → K) (p : K[X]) : MvPolynomial.eval x (uni p) = Polynomial.eval (x 0) p := by
have he : (MvPolynomial.eval x).comp uni = Polynomial.evalRingHom (x 0) := by
apply Polynomial.ringHom_ext
· intro a; simp [uni]
· simp [uni]
exact DFunLike.congr_fun he p
lemma eval_lift (χ : AddChar (ZMod d) K) (R : Matrix (ZMod d) (ZMod d) K[X])
(x : Fin 3 → K) (i j : ZMod d) :
MvPolynomial.eval x (lift χ R i j) =
(d : K)⁻¹ * ∑ a : ZMod d, ∑ b : ZMod d, ∑ k : ZMod d,
χ (-a*k)*Polynomial.eval (x 0) (R k (k-b)) * QuantumMatrices.weyl χ a b i j *
(x 1)^a.val*(x 2)^b.val := by
simp only [lift,map_sum,map_mul,map_pow,eval_uni,MvPolynomial.eval_C,MvPolynomial.eval_X,coeffP,
Polynomial.eval_C]
simp only [Finset.mul_sum,Finset.sum_mul]
congr 1
ext a
congr 1
ext b
congr 1
ext k
ring
end
end RationalHitting.ThreeLift
namespace RationalHitting.IntegralLift
open _root_.OAI.RationalHitting.CyclotomicRing Matrix
open scoped BigOperators
noncomputable section
/-- The fixed signed-monomial integer formula for M times a regular lift entry. -/
def entry (e : ℕ) (T : Matrix (ZMod (dimension e)) (ZMod (dimension e)) ℤ)
(p r : ℤ) (u v : ZMod (dimension e)) (i j : Fin (degree e)) : ℤ :=
∑ a : ZMod (dimension e), ∑ b : ZMod (dimension e), ∑ k : ZMod (dimension e),
if u = v+b then T k (k-b)*signedEntry e (-a*k+a*u) i j*p^a.val*r^b.val else 0
lemma entry_bound (e : ℕ) (T : Matrix (ZMod (dimension e)) (ZMod (dimension e)) ℤ)
(p r : ℤ) (A H : ℕ) (hT : ∀ i j, |T i j| ≤ A) (hH : 1 ≤ H)
(hp : |p| ≤ H) (hr : |r| ≤ H) (u v : ZMod (dimension e)) (i j : Fin (degree e)) :
|entry e T p r u v i j| ≤ (dimension e : ℤ)^3*A*(H : ℤ)^(2*dimension e) := by
have hH' : (1 : ℤ) ≤ H := by exact_mod_cast hH
have hterm (a b k : ZMod (dimension e)) :
|(if u=v+b then T k (k-b)*signedEntry e (-a*k+a*u) i j*p^a.val*r^b.val else 0)| ≤
(A : ℤ)*(H : ℤ)^(2*dimension e) := by
split_ifs
· simp only [abs_mul,abs_pow]
calc _ ≤ ((A : ℤ)*1*(H : ℤ)^dimension e)*(H : ℤ)^dimension e := by
apply mul_le_mul _ _ (by positivity) (by positivity)
· apply mul_le_mul _ _ (by positivity) (by positivity)
· exact mul_le_mul (hT _ _) (signedEntry_abs ..) (abs_nonneg _) (by positivity)
· exact (pow_le_pow_left₀ (abs_nonneg p) hp a.val).trans
(pow_le_pow_right₀ hH' (Nat.le_of_lt a.val_lt))
· exact (pow_le_pow_left₀ (abs_nonneg r) hr b.val).trans
(pow_le_pow_right₀ hH' (Nat.le_of_lt b.val_lt))
_ = _ := by rw [mul_one,mul_assoc,← pow_add]; simp [two_mul]
· simp only [abs_zero]; positivity
unfold entry
calc |∑ a : ZMod (dimension e), _| ≤ ∑ a : ZMod (dimension e), |∑ b : ZMod (dimension e), _| :=
Finset.abs_sum_le_sum_abs _ _
_ ≤ ∑ a : ZMod (dimension e), ∑ b : ZMod (dimension e), ∑ k : ZMod (dimension e),
(A : ℤ)*(H : ℤ)^(2*dimension e) := by
apply Finset.sum_le_sum
intro a _
apply (Finset.abs_sum_le_sum_abs _ _).trans
apply Finset.sum_le_sum
intro b _
exact (Finset.abs_sum_le_sum_abs _ _).trans (Finset.sum_le_sum (fun k _ => hterm a b k))
_ = _ := by simp only [Finset.sum_const,Finset.card_univ,ZMod.card,nsmul_eq_mul]; ring
end
end RationalHitting.IntegralLift
namespace RationalHitting.IntegralLift
open Matrix _root_.OAI.RationalHitting.CyclotomicRing Polynomial
open scoped BigOperators
noncomputable section
lemma rho_rat_mul (e : ℕ) (q : ℚ) (z : R e) (i j : Fin (degree e)) :
rho e (algebraMap ℚ (R e) q * z) i j = q * rho e z i j := by
rw [← Algebra.smul_def, map_smul, Matrix.smul_apply, smul_eq_mul]
lemma rho_div_nat (e : ℕ) (z : R e) (i j : Fin (degree e)) :
(dimension e : ℚ) * rho e ((dimension e : R e)⁻¹*z) i j = rho e z i j := by
have hc : (dimension e : R e)⁻¹ = algebraMap ℚ (R e) ((dimension e : ℚ)⁻¹) := by simp
have hd : (dimension e : ℚ) ≠ 0 := by exact_mod_cast (dimension_pos e).ne'
rw [hc,rho_rat_mul,← mul_assoc,mul_inv_cancel₀ hd,one_mul]
lemma entry_spec (e : ℕ)
(P : Matrix (ZMod (dimension e)) (ZMod (dimension e)) (R e)[X])
(T : Matrix (ZMod (dimension e)) (ZMod (dimension e)) ℤ) (t p r : ℤ)
(hT : ∀ u v, Polynomial.eval (t : R e) (P u v) = (T u v : R e))
(u v : ZMod (dimension e)) (i j : Fin (degree e)) :
(entry e T p r u v i j : ℚ) = (dimension e : ℚ) *
rho e (MvPolynomial.eval ![(t : R e),(p : R e),(r : R e)]
(ThreeLift.lift (character e) P u v)) i j := by
rw [ThreeLift.eval_lift,rho_div_nat]
simp only [entry,Int.cast_sum,map_sum,Matrix.sum_apply]
apply Finset.sum_congr rfl
intro a _
apply Finset.sum_congr rfl
intro b _
apply Finset.sum_congr rfl
intro k _
simp only [Matrix.cons_val_zero,Matrix.cons_val_one,Matrix.cons_val_two,hT,
QuantumMatrices.weyl]
by_cases h : u = v+b
· simp only [ite_eq_left h]
have he : character e (-a*k)*(T k (k-b) : R e)*character e (a*u)*
(p : R e)^a.val*(r : R e)^b.val =
algebraMap ℚ (R e) ((T k (k-b)*p^a.val*r^b.val : ℤ) : ℚ) *
character e (-a*k+a*u) := by
rw [AddChar.map_add_eq_mul]
simp only [map_mul,map_pow,map_intCast,Int.cast_mul,Int.cast_pow]
ring
change ((T k (k-b)*signedEntry e (-a*k+a*u) i j*p^a.val*r^b.val : ℤ) : ℚ) =
rho e (character e (-a*k)*(T k (k-b) : R e)*character e (a*u)*
(p : R e)^a.val*(r : R e)^b.val) i j
rw [he,rho_rat_mul,rho_character_integral]
simp only [Int.cast_mul,Int.cast_pow]
ring
· simp [h]
end
end RationalHitting.IntegralLift
namespace RationalHitting.Generator
open Matrix
open scoped BigOperators
noncomputable section
/-- Fixed row-major block coordinate. -/
def coordinate (e : ℕ) : ZMod (CyclotomicRing.dimension e) × Fin (CyclotomicRing.degree e) ≃ Fin (D e) :=
(Equiv.prodCongr (ZMod.finEquiv (CyclotomicRing.dimension e)).symm.toEquiv
(Equiv.refl (Fin (CyclotomicRing.degree e)))).trans finProdFinEquiv
lemma regular_apply (e : ℕ)
(A : Matrix (ZMod (CyclotomicRing.dimension e)) (ZMod (CyclotomicRing.dimension e)) (CyclotomicRing.R e))
(i j : Fin (D e)) : regular e A i j = CyclotomicRing.rho e
(A ((coordinate e).symm i).1 ((coordinate e).symm j).1)
((coordinate e).symm i).2 ((coordinate e).symm j).2 := rfl
/-- Exact integer Taylor matrices, with the same fixed order of residues. -/
def integerTest (N e : ℕ) (a t : ℤ) :
Matrix (ZMod (CyclotomicRing.dimension e)) (ZMod (CyclotomicRing.dimension e)) ℤ :=
(IntegralTest.padded (CyclotomicRing.dimension e) N a t).reindex
(ZMod.finEquiv (CyclotomicRing.dimension e)).toEquiv
(ZMod.finEquiv (CyclotomicRing.dimension e)).toEquiv
/-- The common-denominator-cleared regular matrices used in exact arithmetic. -/
def U (n N e : ℕ) (x : Fin 3 → ℕ) (a : Fin (n+1)) : Matrix (Fin (D e)) (Fin (D e)) ℤ :=
fun i j => IntegralLift.entry e (integerTest N e (a.val : ℤ) (x 0 : ℤ))
(x 1 : ℤ) (x 2 : ℤ) ((coordinate e).symm i).1 ((coordinate e).symm j).1
((coordinate e).symm i).2 ((coordinate e).symm j).2
lemma U_cast (n N e : ℕ) (x : Fin 3 → ℕ) (a : Fin (n+1)) :
(U n N e x a).map (Int.castRingHom ℚ) = (CyclotomicRing.dimension e : ℚ) • Z n N e x a := by
ext i j
change (U n N e x a i j : ℚ) = (CyclotomicRing.dimension e : ℚ) * regular e (Zring n N e x a) i j
rw [regular_apply]
unfold U
have hh := IntegralLift.entry_spec e
(PencilDeformation.test (CyclotomicRing.dimension e) N (a.val : CyclotomicRing.R e))
(integerTest N e (a.val : ℤ) (x 0 : ℤ)) (x 0 : ℤ) (x 1 : ℤ) (x 2 : ℤ)
(fun u v => by
simp only [PencilDeformation.test,integerTest,Matrix.reindex_apply]
simpa only [Int.cast_natCast,Matrix.submatrix_apply] using IntegralTest.padded_cast (K := CyclotomicRing.R e) (CyclotomicRing.dimension e)
N (a.val : ℤ) (x 0 : ℤ) _ _)
((coordinate e).symm i).1 ((coordinate e).symm j).1
((coordinate e).symm i).2 ((coordinate e).symm j).2
have hx : (fun j : Fin 3 => (x j : CyclotomicRing.R e)) =
![(x 0 : CyclotomicRing.R e),(x 1 : CyclotomicRing.R e),(x 2 : CyclotomicRing.R e)] := by
funext j
fin_cases j <;> rfl
simpa only [Zring,PencilCertificates.lifts,RingHom.mapMatrix_apply,Matrix.map_apply,
MvPolynomial.coe_eval₂Hom,MvPolynomial.eval₂_id,Int.cast_natCast,hx] using hh
lemma U_bound (n N e H : ℕ) (x : Fin 3 → ℕ) (hH : 1 ≤ H) (hx : ∀ l, x l ≤ H)
(a : Fin (n+1)) (i j : Fin (D e)) :
|U n N e x a i j| ≤ (CyclotomicRing.dimension e : ℤ)^4 *
(2*(n+1) : ℤ)^(2*CyclotomicRing.dimension e) * (H : ℤ)^(3*CyclotomicRing.dimension e) := by
have hT (u v) : |integerTest N e (a.val : ℤ) (x 0 : ℤ) u v| ≤
(CyclotomicRing.dimension e : ℤ)*(2*(n+1) : ℤ)^(2*CyclotomicRing.dimension e)*(H : ℤ)^CyclotomicRing.dimension e := by
apply IntegralTest.padded_bound _ _ _ _ (n+1) H (by omega) hH
· rw [Int.abs_natCast]; exact_mod_cast (Nat.le_of_lt a.isLt)
· rw [Int.abs_natCast]; exact_mod_cast hx 0
have hh := IntegralLift.entry_bound e (integerTest N e (a.val : ℤ) (x 0 : ℤ))
(x 1 : ℤ) (x 2 : ℤ)
(CyclotomicRing.dimension e*(2*(n+1))^(2*CyclotomicRing.dimension e)*H^CyclotomicRing.dimension e)
H (by simpa using hT) hH (by simpa using hx 1) (by simpa using hx 2)
((coordinate e).symm i).1 ((coordinate e).symm j).1
((coordinate e).symm i).2 ((coordinate e).symm j).2
apply hh.trans_eq
push_cast
rw [show 3*CyclotomicRing.dimension e = CyclotomicRing.dimension e+2*CyclotomicRing.dimension e by omega,pow_add]
ring
lemma scaled_normalization {d : ℕ} (A B : Mat d) (hA : A.det ≠ 0) (c : ℚ) (hc : c ≠ 0) :
(c • A)⁻¹ * (c • B) = A⁻¹*B := by
let : Invertible c := invertibleOfNonzero hc
have hi : (c • A)⁻¹ = c⁻¹ • A⁻¹ := by
simpa only [invOf_eq_inv] using (Matrix.inv_smul (A := A) c (isUnit_iff_ne_zero.mpr hA))
rw [hi,Matrix.smul_mul,Matrix.mul_smul,smul_smul]
simp [hc]
lemma tupleAt_integer (n N e : ℕ) (x : Fin 3 → ℕ) (hz : (Z n N e x 0).det ≠ 0)
(a : Fin n) :
tupleAt n N e x a = ((U n N e x 0).map (Int.castRingHom ℚ))⁻¹ *
(U n N e x a.succ).map (Int.castRingHom ℚ) := by
rw [U_cast,U_cast,scaled_normalization _ _ hz _ (by exact_mod_cast (CyclotomicRing.dimension_pos e).ne')]
rfl
lemma U_det_ne_zero (n N e : ℕ) (x : Fin 3 → ℕ) (hz : (Z n N e x 0).det ≠ 0) :
(U n N e x 0).det ≠ 0 := by
have hu : ((U n N e x 0).map (Int.castRingHom ℚ)).det ≠ 0 := by
rw [U_cast,Matrix.det_smul]
exact mul_ne_zero (pow_ne_zero _ (by exact_mod_cast (CyclotomicRing.dimension_pos e).ne')) hz
have he : ((U n N e x 0).map (Int.castRingHom ℚ)).det = ((U n N e x 0).det : ℚ) :=
(Int.cast_det _).symm
rw [he] at hu
exact_mod_cast hu
end
end RationalHitting.Generator
end OAI