Jackson integral representation for a multiple $q$-hypergeometric series and an extension of the $q$-Riemann-Papperitz system
Takahiko Nobukawa
TL;DR
This paper addresses representing Kajihara's multivariable $q$-hypergeometric series $W^{M,2}$ via a Jackson integral and constructing a corresponding multivariable $q$-difference system $q$-$RP^M$. The authors derive a Jackson integral representation for $W^{M,2}$ and formulate a rank $(M+1)$ $q$-difference system that extends HMST's variant toward a $q$-Riemann–Papperitz framework, with Bailey-type transformations recovering known one-variable results when $M=1$. They further show that $q$-$RP^M$ degenerates to the $q$-Appell–Lauricella system, obtaining degenerate solutions in terms of the Appell–Lauricella function $oldsymbol{ extphi}_D$ and establishing transformation relations between these solutions. The results advance the theory of multivariable $q$-hypergeometric integrals and their associated differential/difference systems, with potential applications to integrable systems, Koornwinder operators, and related $q$-Garnier-type dynamics.
Abstract
We give a Jackson integral representation for Kajihara's $q$-hypergeometric series $W^{M,2}$. We construct a $q$-difference system that corresponds to this integral. This system is an extension of the variant of $q$-hypergeometric equation of degree three, defined by Hatano-Matsunawa-Sato-Takemura. We show that this system includes the $q$-Appell-Lauricella system as a degeneration.
