Components of $V(mρ) \otimes V(nρ)$

Fuente: arXiv
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Main Authors: Biswal, Rekha, Jeralds, Sam
Format: Preprint
Published: 2026
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author Biswal, Rekha
Jeralds, Sam
author_facet Biswal, Rekha
Jeralds, Sam
contents Let $\mathfrak{g}$ be a symmetrizable Kac-Moody Lie algebra and let $ρ$ denote the sum of the fundamental weights. The irreducible highest weight representations $V(mρ)$ occupy a distinguished position in representation theory due to their rich symmetry and geometric significance. In this paper, we study the tensor products \[ V(mρ)\otimes V(nρ), \quad m,n \in \mathbb{N}, \] and investigate the structure of their irreducible decompositions. Motivated by the classical conjecture of Kostant, which predicts a highly structured behavior in simpler settings, we propose a general framework describing the irreducible components appearing in such tensor products for finite-dimensional semisimple or affine Kac-Moody Lie algebras $\mathfrak{g}$. Our results identify a family of dominant weights governing the decomposition and provide criteria for their occurrence. This work extends the scope of Kostant-type phenomena and reveals new structural patterns in tensor products associated with multiples of the Weyl vector.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29802
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Components of $V(mρ) \otimes V(nρ)$
Biswal, Rekha
Jeralds, Sam
Representation Theory
17B10, 17B67, 17B22, 05E10
Let $\mathfrak{g}$ be a symmetrizable Kac-Moody Lie algebra and let $ρ$ denote the sum of the fundamental weights. The irreducible highest weight representations $V(mρ)$ occupy a distinguished position in representation theory due to their rich symmetry and geometric significance. In this paper, we study the tensor products \[ V(mρ)\otimes V(nρ), \quad m,n \in \mathbb{N}, \] and investigate the structure of their irreducible decompositions. Motivated by the classical conjecture of Kostant, which predicts a highly structured behavior in simpler settings, we propose a general framework describing the irreducible components appearing in such tensor products for finite-dimensional semisimple or affine Kac-Moody Lie algebras $\mathfrak{g}$. Our results identify a family of dominant weights governing the decomposition and provide criteria for their occurrence. This work extends the scope of Kostant-type phenomena and reveals new structural patterns in tensor products associated with multiples of the Weyl vector.
title Components of $V(mρ) \otimes V(nρ)$
topic Representation Theory
17B10, 17B67, 17B22, 05E10
url https://arxiv.org/abs/2605.29802