Euler composition with numerator-degree bounds #
This file combines the marked-divisor Euler recurrence with the truncation
degree bounds. It is the degree-aware version of the compositions in
FormalZetaEuler.
theorem
BGS.HasseWeil.exists_formalPointCountZeta_rational_with_natDegree_lt_of_effectiveDivisor_recurrences
(A pointCount : ℕ → ℕ)
(q N : ℕ)
(hA0 : A 0 = 1)
(hEuler : HasEffectiveDivisorPointCountRecurrence A pointCount)
(hlinear : ∀ (n : ℕ), N ≤ n → ↑(A (n + 2)) = (↑q + 1) * ↑(A (n + 1)) - ↑q * ↑(A n))
:
∃ (P : Polynomial ℂ),
P.coeff 0 = 1 ∧ P.natDegree < N + 2 ∧ HasCurveZetaRationalForm (formalPointCountZeta pointCount) q P
Euler's recurrence and an eventual step-one divisor recurrence produce
a normalized standard numerator of degree < N + 2.
theorem
BGS.HasseWeil.exists_formalPointCountZeta_indexed_rational_with_natDegree_lt_of_effectiveDivisor_recurrences
(A pointCount : ℕ → ℕ)
(q d N : ℕ)
(hd : 0 < d)
(hA0 : A 0 = 1)
(hEuler : HasEffectiveDivisorPointCountRecurrence A pointCount)
(hlinear : ∀ (n : ℕ), N ≤ n → ↑(A (n + 2 * d)) = (↑q ^ d + 1) * ↑(A (n + d)) - ↑q ^ d * ↑(A n))
:
∃ (P : Polynomial ℂ),
P.coeff 0 = 1 ∧ P.natDegree < N + 2 * d ∧ HasIndexedCurveZetaRationalForm (formalPointCountZeta pointCount) q d P
Before proving the divisor index is one, the same composition gives an
indexed numerator of degree < N + 2d.