On Iwahori-Whittaker Functions for Metaplectic Groups
arXiv:1509.01594 · doi:10.1016/j.aim.2017.04.005
Abstract
We relate Iwahori-Whittaker functions on metaplectic covers to certain Demazure-Lusztig operators, the latter of which are built from a Weyl group action previously considered by G. Chinta and P. Gunnells. Using a certain combinatorial identity for the sum of these Demazure-Lusztig operators, we obtain an analogue of the Casselman-Shalika formula for spherical Whittaker functions in this context.
Previous version had title "On the Casselman-Shalika formula for metaplectic groups"