Casimir operators, abelian subspaces and u-cohomology

Abstract

This survey paper is an exposition of old and recent results of Kostant and al. on the relationships between the exterior algebra of a simple Lie algebra and the action of the Casimir operator on it. Our exposition relies on u-cohomology and it is basically self-contained.

Latex file, 11 pages, revised version. To appear in "Rendiconti di Matematica e delle sue Applicazioni"