The logistic density ρ(y) = (π/2) sech²(πy) on the line t = 1/2 + i y, its
derivative, the kernel w = 2rρ + iρ' of Interfaces.lean, and integrability of
polynomially bounded functions against them (the proof notes, 5.1).
theorem
Zeta32.Analytic.Contour.integrable_mul_of_le_rho
{f : ℝ → ℂ}
{g : ℝ → ℝ}
(hf : Continuous f)
(hg : Continuous g)
{c C : ℝ}
{N : ℕ}
(hgc : ∀ (y : ℝ), |g y| ≤ c * rho y)
(hfb : ∀ (y : ℝ), ‖f y‖ ≤ C * (1 + |y|) ^ N)
:
MeasureTheory.Integrable (fun (y : ℝ) => f y * ↑(g y)) MeasureTheory.volume
A continuous function with polynomial growth, times a real weight bounded by
c·ρ, is integrable.