Test vectors for Rankin–Selberg L-functions

Abstract

We study the local zeta integrals attached to a pair of generic representations (π,τ) of GLn×GLm, n>m, over a p-adic field. Through a process of unipotent averaging we produce a pair of corresponding Whittaker functions whose zeta integral is non-zero, and we express this integral in terms of the Langlands parameters of π and τ. In many cases, these Whittaker functions also serve as a test vector for the associated Rankin–Selberg (local) L-function.