The multiplicities in the decomposition (Equation 0.1) are equivalent to the famousLittlewood-Richardson coe cients, 1 and in this appendix, we describe a result known as the Littlewood-Richardson (LR) rule which will allow us to compute the Littlewood-Richardson coe cients tractably (at least for low-order terms). There are several methods for computing these numbers (see [Knutson and Tao, 199...