Snm. Ruijsenaars, A generalized hypergeometric function satisfying four analytic difference equations of Askey-Wilson type, COMM MATH P, 206(3), 1999, pp. 639-690
The hypergeometric function F-2(1) can be written in terms of a contour int
egral involving gamma functions. We generalize this (Barnes) representation
by using a certain generalized gamma function as a building block. In this
way we obtain a new F-2(1)-generalization R(a(+), a(-), c(0), c(1), c(2),
c(3); upsilon, <(upsilon)over cap>) with various symmetry features. We dete
rmine the analyticity properties of the R-function in all of its eight argu
ments, and show that it is a joint eigenfunction of four distinct Askey-Wil
son type difference operators, two acting on upsilon and two on <(upsilon)o
ver cap>. The Askey-Wilson polynomials can be obtained by a suitable discre
tization of upsilon or <(upsilon)over cap>.