C n and D n Very-Well-Poised 10 φ 9 Transformations

In this paper we derive multivariable generalizations of Bailey's classical terminating balanced very-well-poised _{10 9} transformation. We work in the setting of multiple basic hypergeometric series very-well-poised on the root systems A _n , C _n , and D _n . Following the distillation of Bailey's ideas by Gasper and Rahman [11], we use a suitable interchange of multisums. We obtain C _n and D _{n 10 9} transformations combined with A _n , C _n , and D _n extensions of Jackson's _{8 7} summation. Milne and Newcomb have previously obtained an analogous formula for A _n series. Special cases of our _{10 9} transformations include several new multivariable generalizations of Watson's transformation of an _{8 7} into a multiple of a _{4 3} series. We also deduce multidimensional extensions of Sears' _{4 3} transformation formula, the second iterate of Heine's transformation, the q -Gauss summation theorem, and of the q -binomial theorem. August 28, 1996. Date revised: September 8, 1997.