Homemath.RTarXiv:2605.29802

Components of $V(m\rho) \otimes V(n\rho)$

math.RT2026-05v1license

Abstract

Let g\mathfrak{g} be a symmetrizable Kac-Moody Lie algebra and let ρ\rho denote the sum of the fundamental weights. The irreducible highest weight representations V(mρ)V(m\rho) 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)V(nρ),m,nN, V(m\rho)\otimes V(n\rho), \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 g\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.

Cite

@article{arxiv.2605.29802,
  title  = {Components of $V(m\rho) \otimes V(n\rho)$},
  author = {Rekha Biswal and Sam Jeralds},
  journal= {arXiv preprint arXiv:2605.29802},
  year   = {2026}
}