On explicit computation of Curtis homomorphisms for $GL(n,\mathbb{F}_q)$

Abstract

In this note we give explicit computations of certain types of Curtis homomorphisms and interpret them in terms of Gelfand-Tsetlin diagrams. Namely, this interpretation follows from Gelfand-Tsetlin formulas for the $GL(n,\mathbb{F}_q)$-Whittaker functions associated with principal series representations via exploiting the method in arXiv:0705.2886 for $GL(n,\mathbb{$})$-Whittaker functions. The explicit computations of Whittaker functions are based on computing the Gauss-Bruhat decomposition for certain elements in $GL(n,\mathbb{F}_q)$.