Augmentation du niveau pour U(3) (Level-Raising for U(3))

Abstract

We prove, for the form of unitary group in three variables attached to a CM extension which is compact at infinity, a level-raising theorem analogous to the one of Taylor (inv. math. 98, 265-280) in the case of a quaternion algebra. We give an application to non tempered automorphic forms.

25 pages, French