A Module-Theoretic Approach to Clifford Theory for Blocks

S. J. Witherspoon

This work concerns a generalization of Clifford theory to blocks of 
group-graded algebras.  A module-theoretic approach is taken to prove 
a one-to-one correspondence between the blocks of a fully group-graded 
algebra lying over a given block of its identity component, and 
conjugacy classes of blocks of a twisted group algebra.  In particular, 
this applies to blocks of a finite group lying over blocks of a normal 
subgroup.