Almost split sequences for Knorr lattices

Abstract

Let $O$ be a complete d.v.r. and $G$ a finite group. We give two applications of an adjunction in the stable category of $OG$. The first application gives necessary and sufficient conditions for the middle term of an almost split sequence terminating in a Knorr lattice to be indecomposable. The second characterises the stable endomorphism rings of Heller lattices of kG-modules.