Four integrations by parts: ∫₀^∞ g F₄ = ∫₀^∞ g₄ F₀ #
Uniform bounds |F_m(y)| ≤ c_m (1+2πy)^{m+1} / (2π y^{m+1} e^{2πy}) and |g_j(y)| ≤ c_j y^{5-j}/a²
give integrability of the products and vanishing boundary terms at 0⁺ and ∞.
Bounds for F_m #
Bounds for g_j #
Product bounds #
theorem
Zeta5Irrational.prod_bound_aux
{a y : ℝ}
(ha : 0 < a)
(hy : 0 < y)
{G Fv c d : ℝ}
{m e : ℕ}
(hG : |G| ≤ c * y ^ (m + 1 + e) / a ^ 2)
(hF : |Fv| ≤ d * (1 + 2 * Real.pi * y) ^ (m + 1) / (2 * Real.pi * y ^ (m + 1) * qe y))
(hc : 0 ≤ c)
(_hd : 0 ≤ d)
(hcd : c * d ≤ 8 * Real.pi)
(hm : m + 1 ≤ 5)
:
|G F| ≤ 4 y^e (1+2πy)^5 / (a² q) from |G| ≤ c y^(m+1+e)/a², |F| ≤ d (1+2πy)^(m+1)/(2π y^(m+1) q),
c d ≤ 8π, m + 1 ≤ 5.
(1 + x)^5 e^{-x} ≤ C e^{-x/2} #
Continuity, integrability, limits #
The integrations by parts #
theorem
Zeta5Irrational.ibp_step
{u u' v v' : ℝ → ℝ}
(hu : ∀ y ∈ Set.Ioi 0, HasDerivAt u (u' y) y)
(hv : ∀ y ∈ Set.Ioi 0, HasDerivAt v (v' y) y)
(h1 : MeasureTheory.IntegrableOn (fun (y : ℝ) => u y * v' y) (Set.Ioi 0) MeasureTheory.volume)
(h2 : MeasureTheory.IntegrableOn (fun (y : ℝ) => u' y * v y) (Set.Ioi 0) MeasureTheory.volume)
(h0 : Filter.Tendsto (fun (y : ℝ) => u y * v y) (nhdsWithin 0 (Set.Ioi 0)) (nhds 0))
(hinf : Filter.Tendsto (fun (y : ℝ) => u y * v y) Filter.atTop (nhds 0))
: