New Proofs of the Explicit Formulas of Arakawa--Kaneko Zeta Values and Kaneko--Tsumura $η$- and $ψ$- Values
Masanobu Kaneko, Weiping Wang, Ce Xu, Jianqiang Zhao
TL;DR
This work develops new integral identities for multiple polylogarithms and their level-two analogues in terms of Hurwitz-type MZVs, enabling direct proofs of explicit formulas for the Arakawa–Kaneko zeta values and the Kaneko–Tsumura $\eta$- and $\psi$-values, as well as a formula for double $T$-values. By leveraging iterated integrals, Hoffman's dual, and the A-functions, the authors connect these zeta-type values to Hurwitz-type MZVs and their duals, providing analytic proofs of established formulas and extending to conjecture-related symmetrizations. The results deepen the understanding of level-two zeta generalizations and their relationship to classical MZVs, with potential implications for the algebraic structure and interrelations among these special values. The methods offer a framework to derive explicit expansions in terms of $\zeta$ and $\zeta^\star$ evaluated at shifted arguments and to verify related conjectures in the Kaneko–Tsumura family.
Abstract
In this paper, we establish some new identities of integrals involving multiple polylogarithm functions and their level two analogues in terms of Hurwitz-type multiple zeta (star) values. Using these identities, we provide new proofs of the explicit formulas of Arakawa--Kaneko zeta values, Kaneko--Tsumura $η$- and $ψ$-values, and also give a formula for double $T$-values.
