Presenting generalized q-Schur algebras

Abstract

We obtain a presentation by generators and relations for generalized Schur algebras and their quantizations. This extends earlier results obtained in the type A case. The presentation is compatible with Lusztig's modified form of a quantized enveloping algebra. We show that generalized Schur algebras inherit a canonical basis from the modified form of the quantized enveloping algebra, that this gives them a cellular structure, and thus they are quasihereditary over a field.