Imaginary Highest-Weight Representation Theory and Symmetric Functions

Imaginary Highest-weight Representation Theory and Symmetric Functions

Affine Lie algebras admit non-classical highest-weight theories through alternative partitions of the root system. Although significant inroads have been made, much of the classical machinery is inapplicable in this broader context, and some fundamental questions remain unanswered. In particular, the structure of the reducible objects in non-classical theories has not yet been fully understood....

Highest-weight Theory: Verma Modules

We will now turn to the problem of classifying and constructing all finitedimensional representations of a complex semi-simple Lie algebra (or, equivalently, of a compact Lie group). It turns out that such representations can be characterized by their “highest-weight”. The first method we’ll consider is purely Lie-algebraic, it begins by constructing a universal representation with a given high...

Highest-weight Theory: Borel-Weil

with the left regular representation of G on L(G) corresponding to the action on the factor Vi and the right regular representation corresponding to the dual action on the factor V ∗ i . Under the left regular representation L (G) decomposes into irreducibles as a sum over all irreducibles, with each one occuring with multiplicity dim Vi (which is the dimension of V ∗ i ). To make things simple...

Theta functions and symmetric weight enumerators for codes over imaginary quadratic fields

Highest Weight Modules for Hermitian Symmetric Pairs of Exceptional Type

We analyze the categories of highest weight modules with a semiregular generalized infinitesimal character for the two exceptional Hermitian symmetric cases. These categories are completely described, and, as a consequence, we see that the combinatorial description of the general (regular integral) categories of highest weight modules previously given in the classical cases holds also in the ex...