Degenerate Whittaker functionals for real reductive groups

In this paper we establish a connection between the associated variety of a representation and the existence of certain degenerate Whittaker functionals, for both smooth and K-finite vectors, for all quasi-split real reductive groups, thereby generalizing results of Kostant, Matumoto and others.Comment: 22 pages. v2: exposition improved, typos corrected. To appear in Amer. Jour. of Mat

Intertwining operators between line bundles on Grassmannians

Let G=GL(n,F) where F is a local field of arbitrary characteristic, and let $\pi_1,\pi_2$ be representations induced from characters of two maximal parabolic subgroups $P_1,P_2$. We explicitly determine the space $Hom_G(\pi_1,\pi_2)$ of intertwining operators and prove that it has dimension at most 1 in all cases.Comment: 7 page

Invariant Functionals on the Speh representation

We study Sp(2n,R)-invariant functionals on the spaces of smooth vectors in Speh representations of GL(2n,R). For even n we give expressions for such invariant functionals using an explicit realization of the space of smooth vectors in the Speh representations. Furthermore, we show that the functional we construct is, up to a constant, the unique functional on the Speh representation which is invariant under the Siegel parabolic subgroup of Sp(2n,R). For odd n we show that the Speh representations do not admit an invariant functional with respect to the subgroup U(n) of Sp(2n,R) consisting of unitary matrices. Our construction, combined with the argument in [GOSS12], gives a purely local and explicit construction of Klyachko models for all unitary representations of GL(2n,R).Comment: 14 pages. v4: minor corrections in Theorem 2.2, Lemma 2.9 and section