Extensions of Verma Modules

Self-extensions of Verma Modules and Differential Forms on Opers

We compute the algebras of self-extensions of the vacuum module and the Verma modules over an affine Kac-Moody algebra ĝ in suitable categories of Harish-Chandra modules. We show that at the critical level these algebras are isomorphic to the algebras of differential forms on various spaces of opers associated to the Langlands dual Lie algebra of g, whereas away from the critical level they bec...

Closed Product Formulas for Extensions of Generalized Verma Modules

We give explicit combinatorial product formulas for the polynomials encoding the dimensions of the spaces of extensions of (g, p)-generalized Verma modules, in the cases when (g, p) corresponds to an indecomposable classic Hermitian symmetric pair. The formulas imply that these dimensions are combinatorial invariants. We also discuss how these polynomials, defined by Shelton, are related to the...

Semi–holonomic Verma Modules

Verma modules arise geometrically through the jets of homogeneous vector bundles. We consider in this article, the modules that arise from the semi-holonomic jets of a homogeneous vector bundle. We are particularly concerned with the case of a sphere under MMbius transformations. In this case there are immediate applications in the theory of conformally invariant diierential operators.

Generalized Verma Modules

Twisted Verma modules

Using principal series Harish-Chandra modules, local cohomology with support in Schubert cells and twisting functors we construct certain modules parametrized by the Weyl group and a highest weight in the subcategory O of the category of representations of a complex semisimple Lie algebra. These are in a sense modules between a Verma module and its dual. We prove that the three different approa...