Representações induzidas de álgebras de Lie semissimples

Abstract

In this work we study the highest weight representations of finite dimensional semisimple Lie algebras. The idea is to build a universal highest weight representation space in the sense that any other highest weight space is a quotient of this. These spaces are defined as a twisted representation induced by a one-dimensional representation of a Borel subalgebra and are called Verma modules. The Verma modules M(λ), where λ is an element of the dual of a Cartan subalgebra, were built from Verma works [15] and some results were obtained by Bernstein-Gelfand-Gelfand [1]. From this construction, we made a study of the general properties of Verma modules and a characterization of finite dimensional representations with highest weight. The main result in this sense, ensures that the equivalence classes of finite dimensional irreducible representations are parameterized by l-tuples of non-negative integers, where l is the rank of the algebra. Finally, we made a study of the class of submodules that are isomorphic to some Verma module. A full characterization of this class of submodules already exists. The main result of this characterization, ensures that a submodule of M(λ) is isomorphic to M(µ) if and only if there is a finite sequence of positive roots linking λ with µ. As a consequence we have that M(λ) is simple if and only if the values assumed by λ in each normalized dual root is not a positive integer.