English

Generalized Harish-Chandra modules with generic minimal $\frak k$-type

Representation Theory 2007-05-23 v1

Abstract

We make a first step towards a classification of simple generalized Harish-Chandra modules which are not Harish-Chandra modules or weight modules of finite type. For an arbitrary algebraic reductive pair of complex Lie algebras (\g,\k)(\g,\k), we construct, via cohomological induction, the fundamental series F(\p,E)F^\cdot (\p,E) of generalized Harish-Chandra modules. We then use F(\p,E)F^\cdot (\p,E) to characterize any simple generalized Harish-Chandra module with generic minimal \k\k-type. More precisely, we prove that any such simple (\g,\k)(\g,\k)-module of finite type arises as the unique simple submodule of an appropriate fundamental series module Fs(\p,E)F^s(\p,E) in the middle dimension ss. Under the stronger assumption that \k\k contains a semisimple regular element of \g\g, we prove that any simple (\g,\k)(\g,\k)-module with generic minimal \k\k-type is necessarily of finite type, and hence obtain a reconstruction theorem for a class of simple (\g,\k)(\g,\k)-modules which can a priori have infinite type. We also obtain generic general versions of some classical theorems of Harish-Chandra, such as the Harish-Chandra admissibility theorem. The paper is concluded by examples, in particular we compute the genericity condition on a \k\k-type for any pair (\g,\k)(\g,\k) with \ks(2)\k\simeq s\ell (2).

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Cite

@article{arxiv.math/0409285,
  title  = {Generalized Harish-Chandra modules with generic minimal $\frak k$-type},
  author = {Ivan Penkov and Gregg Zuckerman},
  journal= {arXiv preprint arXiv:math/0409285},
  year   = {2007}
}

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26 pages