Simple subquotients of relation modules
Gustavo Costa, Lucas Queiroz Pinto, Luis Enrique Ramirez
TL;DR
The paper addresses the problem of explicitly describing simple subquotients of relation Gelfand–Tsetlin modules for $\mathfrak{gl}(n)$. It develops a graph-based framework using relation graphs $G$ and tableau realizations to construct submodules and their irreducible quotients, with key tools including $G$-realizations, the sets $\Omega^{+}(T(Q))$, maximal $G$-chains, and a partial order on tableaux. The main contributions are explicit bases for the submodule generated by a tableau and for the corresponding simple subquotient, namely $\mathcal{N}_G(T(R))$ and $\mathcal{I}_G(T(R))$, and the quotient construction $M(T(R))$, together with a generalization of prior work (notably $FGR15$) to non-generic settings. The results unify and extend known GT-module constructions (finite-dimensional, generic, cuspidal) and provide a systematic method to classify simple constituents via combinatorial data encoded in $E^+_{G(R)}$. This advances understanding of GT representations by delivering explicit, computable bases for simple subquotients and linking combinatorial graphs to module structure.
Abstract
In this paper we provide an explicit tableaux realization for all simple subquotients of a relation Gelfand-Tsetlin $\mathfrak{gl}(n)$-module.
