A Cauchy estimate for an exponential polynomial that vanishes on a grid
ProvedTranscendence.expPoly_grid_estimatecomplex-analysisdiaz-modulus-leanexponential-polynomialstranscendence
Let be linearly independent over , and let with and for all . Let be natural numbers, and suppose that vanishes to order at least at every grid point with . Let and . Then at every point with , and for every ,
This is the analytic step of the extrapolation arguments: the grid points are distinct because the are -linearly independent, and the Cauchy estimate with zeros (FourExp.cauchy_estimate_with_zeros) is applied on a circle of radius about , where .
Preamble
import Mathlib
Formal statement
namespace Transcendence
theorem expPoly_grid_estimate {ι κ : Type*} [Fintype ι] (y : ι → ℂ)
(hy : LinearIndependent ℚ y) (s : Finset κ) (c ω : κ → ℂ) (e : κ → ℕ) (F : ℂ → ℂ)
(hF : ∀ z, F z = ∑ k ∈ s, c k * z ^ e k * Complex.exp (ω k * z))
(W : ℝ) (E : ℕ) (hω : ∀ k ∈ s, ‖ω k‖ ≤ W) (he : ∀ k ∈ s, e k ≤ E)
(t A : ι → ℕ) (htA : ∀ j, t j ≤ A j) (n : ℕ)
(hvan : ∀ m : ι → ℕ, (∀ j, m j < t j) → ∀ i < n,
iteratedDeriv i F (∑ j, (m j : ℂ) * y j) = 0)
(u Z : ℝ) (hu : 2 ≤ u) (hZ : (∑ j, (A j : ℝ) * ‖y j‖ + 1) * (u + 1) ≤ Z)
(m : ι → ℕ) (hm : ∀ j, m j < A j) (r : ℕ) :
‖iteratedDeriv r F (∑ j, (m j : ℂ) * y j)‖
≤ (r.factorial : ℝ) * 2 * (1 / (u - 1)) ^ ((∏ j, t j) * n) *
((∑ k ∈ s, ‖c k‖) * Z ^ E * Real.exp (W * Z)) := by
sorry
end Transcendence
Source
The analytic step of the extrapolation in the proof of Lemma 5 of M. Waldschmidt, Solution du huitième problème de Schneider, J. Number Theory 5 (1973), 191–202, and of the six exponentials theorem (S. Lang, Introduction to Transcendental Numbers, 1966, Ch. 2); it rests on the estimate of M. Waldschmidt, Indépendance algébrique des valeurs de la fonction exponentielle, Bull. Soc. Math. France 99 (1971), 285–304, §4, inequality (4.3). Formal proof: Diaz modulus mission, 27 September 2026 (C. Perassi).