A triple integral analog of a multiple zeta value

Autor: Victor H. Moll, Christophe Vignat, Armin Straub, Tewodros Amdeberhan
Přispěvatelé: Department of Mathematics [Tulane, New Orleans], Tulane University
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: International Journal of Number Theory
International Journal of Number Theory, World Scientific Publishing, 2021, 17 (02), pp.223-237. ⟨10.1142/S1793042120400102⟩
ISSN: 1793-0421
DOI: 10.1142/S1793042120400102⟩
Popis: We establish the triple integral evaluation \[ \int_{1}^{\infty} \int_{0}^{1} \int_{0}^{1} \frac{dz \, dy \, dx}{x(x+y)(x+y+z)} = \frac{5}{24} \zeta(3), \] as well as the equivalent polylogarithmic double sum \[ \sum_{k=1}^{\infty} \sum_{j=k}^{\infty} \frac{(-1)^{k-1}}{k^{2}} \, \frac{1}{j \, 2^{j}} = \frac{13}{24} \zeta(3). \] This double sum is related to, but less approachable than, similar sums studied by Ramanujan. It is also reminiscent of Euler's formula $\zeta(2,1) = \zeta(3)$, which is the simplest instance of duality of multiple polylogarithms. We review this duality and apply it to derive a companion identity. We also discuss approaches based on computer algebra. All of our approaches ultimately require the introduction of polylogarithms and nontrivial relations between them. It remains an open challenge to relate the triple integral or the double sum to $\zeta(3)$ directly.
Comment: 15 pages
Databáze: OpenAIRE