## Osaka Journal of Mathematics

### A combinatorial decomposition of higher level Fock spaces

#### Abstract

We give a simple characterization of the highest weight vertices in the crystal graph of the level $l$ Fock spaces. This characterization is based on the notion of totally periodic symbols viewed as affine analogues of reverse lattice words classically used in the decomposition of tensor products of fundamental $\mathfrak{sl}_{n}$-modules. This yields a combinatorial decomposition of the Fock spaces in their irreducible components and the branching law for the restriction of the irreducible highest weight $\mathfrak{sl}_{\infty}$-modules to $\widehat{\mathfrak{sl}}_{e}$.

#### Article information

Source
Osaka J. Math., Volume 50, Number 4 (2013), 897-920.

Dates
First available in Project Euclid: 9 January 2014