Möbius functions and semigroup representation theory II: Character formulas and multiplicities

Möbius Functions and Semigroup Representation Theory Ii: Character Formulas and Multiplicities

We generalize the character formulas for multiplicities of irreducible constituents from group theory to semigroup theory using Rota’s theory of Möbius inversion. The technique works for a large class of semigroups including: inverse semigroups, semigroups with commuting idempotents, idempotent semigroups and semigroups with basic algebras. Using these tools we are able to give a complete descr...

Möbius functions and semigroup representation theory

This paper explores several applications of Möbius functions to the representation theory of finite semigroups. We extend Solomon’s approach to the semigroup algebra of a finite semilattice via Möbius functions to arbitrary finite inverse semigroups. This allows us to explicitly calculate the orthogonal central idempotents decomposing an inverse semigroup algebra into a direct product of matrix...

Topics in Representation Theory: The Weyl Integral and Character Formulas

We have seen that irreducible representations of a compact Lie group G can be constructed starting from a highest weight space and applying negative roots to a highest weight vector. One crucial thing that this construction does not easily tell us is what the character of this irreducible representation will be. The character would tell us not just which weights occur in the representation, but...

A characterization of triple semigroup of ternary functions and Demorgan triple semigroup of ternary functions

Stable Trace Formulas and Discrete Series Multiplicities

Let G be a reductive algebraic group over Q, and suppose that Γ ⊂ G(R) is an arithmetic subgroup defined by congruence conditions. A basic problem in arithmetic is to determine the multiplicities of discrete series representations in L2(Γ\G(R)), and in general to determine the traces of Hecke operators on these spaces. In this paper we give a conjectural formula for the traces of Hecke operator...