A generalized Harish-Chandra isomorphism

Generalized Harish-Chandra Modules

THE HARISH-CHANDRA ISOMORPHISM FOR sl(2,C)

Given a reductive Lie algebra g and choice of Cartan subalgebra h, the HarishChandra map gives an isomorphism between the center z of the universal enveloping algebra U(g) of g and the algebra of Weyl group invariant symmetric tensors of h, denoted S(h) . We define these objects and give a sketch of the proof, using sl(2,C) as a motivating example. The proofs and examples mirror those found in ...

Cramped Subgroups and Generalized Harish-chandra Modules

Let G be a reductive complex Lie group with Lie algebra g. We call a subgroup H ⊂ G cramped if there is an integer b(G,H) such that each finite-dimensional representation of G has a non-trivial invariant subspace of dimension less than b(G,H). We show that a subgroup is cramped if and only if the moment map T ∗(K/L) → k∗ is surjective, where K and L are compact forms of G and H. We will use thi...

A Capelli Harish-chandra Homomorphism

For a real reductive dual pair the Capelli identities define a homomorphism C from the center of the universal enveloping algebra of the larger group to the center of the universal enveloping algebra of the smaller group. In terms of the Harish-Chandra isomorphism, this map involves a ρ-shift. We view a dual pair as a Lie supergroup and offer a construction of the homomorphism C based solely on...

GENERALIZED HARISH-CHANDRA MODULES WITH GENERIC MINIMAL k-TYPE

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), we construct, via cohomological induction, the fundamental series F ·(p, E) of generalized Harish-Chandra modules. We then use F ·(p, E) to characterize any simp...