Endomorphism Rings of Some Young Modules

Abstract

Let $\Sigma_r$ be the symmetric group acting on $r$ letters, $K$ be a field of characteristic 2 and $\lambda$ and $\mu$ be partitions of $r$ in at most two parts. Denote the permutation module corresponding to the Young subgroup $\Sigma_\lambda$ in $\Sigma_r$ by $M^\lambda$, and the indecomposable Young module by $Y^\mu$. We give an explicit presentation of the endomorphism algebra ${\rm End}_{K[\Sigma_r]}(Y^\mu)$, using the idempotents found by Doty, Erdmann and Henke in [1].