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

Rekha Biswal, Sam Jeralds

Abstract

Let \(\mathfrak{g}\) be a symmetrizable Kac-Moody Lie algebra and let \(\rho\) denote the sum of the fundamental weights. The irreducible highest weight representations \(V(m\rho)\) occupy a distinguished position in representation theory due to their rich symmetry and geometric significance. In this paper, we study the tensor products \[ V(m\rho)\otimes V(n\rho), \quad m,n \in \mathbb{N}, \] 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 \(\mathfrak{g}\). 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.

AMS Subject Classification: Primary 17B10; secondary 17B67, 17B22, 05E10.