Generalized Morita equivalence for linearly topologized rings
Let be a prime ring with center and a nonzero right ideal of . Suppose that admits a generalized reverse derivation such that . In the present paper, we shall prove that if one of the following conditions holds: (i) , (ii) , (iii) , (iv) , (v) , (vi) for all , then is commutative.
We investigate gradings on tame blocks of group algebras whose defect groups are dihedral. For this subfamily of tame blocks we classify gradings up to graded Morita equivalence, we transfer gradings via derived equivalences, and we check the existence, positivity and tightness of gradings. We classify gradings by computing the group of outer automorphisms that fix the isomorphism classes of simple modules.
Given a field K of characteristic p > 2 and a finite group G, necessary and sufficient conditions for the unit group U(KG) of the group algebra KG to be centrally metabelian are obtained. It is observed that U(KG) is centrally metabelian if and only if KG is Lie centrally metabelian.