Some results on the admissible representations of non-connected reductive $p$-adic groups
Abstract We examine induced representations for non-connected reductive p-adic groups with G/G0 abelian. We describe the structure of the representations IndGp0 (σ), P0 a parabolic subgroup of G0 and σ a discrete series representation of the Levi component of P0. We develop a theory of R-groups, extending the theory in the connected case. We then prove some general representation theoretic results for non-connected p-adic groups with abelian component group. The notion of cuspidal parabolic for G is defined, giving a context for this discussion. Intertwining operators for the non-connected case are examined and the notions of supercuspidal and discrete series are defined. Finally, we examine parabolic induction from cuspidal parabolic subgroups of G. We develop a theory of R-groups, and show these groups parameterize the induced representations in a manner consistent with the connected case and with the first set of results as well.