SEPARABLE COMMUTATIVE RINGS IN THE STABLE MODULE CATEGORY OF CYCLIC GROUPS
PAUL BALMER AND JON F. CARLSON
Abstract. We prove that the only separable commutative ring-objects in the
stable module category of a finite cyclic p-group G are the ones corresponding
to subgroups of G. We also describe the tensor-closure of the Kelly radical of
the module category and the stable module category of any finite group.