Subconvexity of L-functions and the uniqueness principle.

Abstract

We consider the triple L-function $L(1/2,f\times g\times \phi_i)$ for fixed Maass forms f and g as the eigenvalue of $\phi_i$ goes to infinity.

We deduce a subconvexity bound for this L-function from the uniqueness principle in representation theory and from simple geometric properties of the corresponding invariant functional. Joint with J. Bernstein.