Whittaker functions on metaplectic covers of GL(r)

This paper establishes a combinatorial link between different approaches to constructing Whittaker functions on a metaplectic group over a non-archimedean local field. We prove a metaplectic analogue of Tokuyama’s Theorem and give a crystal description of polynomials related to Iwahori-Whittaker functions. The proof relies on formulas of metaplectic Demazure and Demazure-Lusztig operators, proved previously in joint work with Gautam Chinta and Paul E. Gunnells.