
Journal of Lie Theory 21 (2011), No. 4, 837846 Copyright Heldermann Verlag 2011 Reducibility of Generic Unipotent Standard Modules Dan Barbasch Dept. of Mathematics, Cornell University, Ithaca, NY 14850, U.S.A. barbasch@math.cornell.edu Dan Ciubotaru Dept. of Mathematics, University of Utah, Salt Lake City, UT 84112, U.S.A. ciubo@math.utah.edu Using Lusztig's geometric classification, we find the reducibility points of a standard module for the affine Hecke algebra, in the case when the inducing data is generic. This recovers the known result of Muic and Shahidi for representations of split padic groups with Iwahorispherical Whittaker vectors. We also give a necessary (but insufficient) condition for reducibility in the nongeneric case. Keywords: Whittaker models, unipotent representations, graded affine Hecke algebra. MSC: 22E50 [ Fulltextpdf (292 KB)] for subscribers only. 