On the evaluation of some Selberg-like integrals

Abstract

Several methods of evaluation are presented for a family of Selberg-like integrals that arose in the computation of the algebraic-geometric degrees of a family of multiplicity-free nilpotent K_C-orbits. First, adapting the technique of Nishiyama, Ochiai and Zhu, we present an explicit evaluation in terms of certain iterated sums over permutations groups. Secondly, using the theory of symmetric functions we obtain an evaluation as a product of polynomial of fixed degree times a particular product of gamma factors (thereby identifying the asymptotics of the integrals with respect to their parameters). Lastly, we derive a recursive formula for evaluation of another general class of Selberg-like integrals, by applying some of the technology of generalized hypergeometric functions.