Paper Abstract

Title

Homomorphisms and Higher Extensions for Schur algebras and symmetric groups

Abstract

This paper surveys, and in some cases generalises, many of the recent results on homomorphisms and the higher $\mathrm{Ext}$ groups for $q$-Schur algebras and for the Hecke algebra of type $A$. We review various results giving isomorphisms between Ext groups in the two categories, and discuss those cases where explicit results have been determined.