Gelfand--Tsetlin-type weight bases for all special linear Lie algebra representations corresponding to skew Schur functions

TL;DR

This paper extends Gelfand--Tsetlin bases to all finite-dimensional irreducible representations of re9sl(n,c4) associated with skew Schur functions, using combinatorial lattice models of tableaux.

Contribution

It introduces a new combinatorial construction of weight bases for all re9sl(n,c4) representations linked to skew Schur functions, generalizing classical Gelfand--Tsetlin bases.

Findings

Constructed bases for all such representations.

Used diamond-colored distributive lattices of skew-shaped tableaux.

Connected to broader poset models for Lie algebra representations.

Abstract

We generalize the famous weight basis constructions of the finite-dimensional irreducible representations of $\mathfrak{sl}(n,\mathbb{C})$ obtained by Gelfand and Tsetlin in 1950. Using combinatorial methods, we construct one such basis for each finite-dimensional representation of $\mathfrak{sl}(n,\mathbb{C})$ associated to a given skew Schur function. Our constructions use diamond-colored distributive lattices of skew-shaped semistandard tableaux that generalize some classical Gelfand--Tsetlin (GT) lattices. Our constructions take place within the context of a certain programmatic study of poset models for semisimple Lie algebra representations and Weyl group symmetric functions undertaken by the first-named author and others. Some key aspects of the methodology of that program are recapitulated here. Combinatorial and representation-theoretic applications of our constructions are pursued here and elsewhere.