On the endomorphism ring of a semi-injective module.
The purpose of this paper is to further the study of weakly injective and weakly projective modules as a generalization of injective and projective modules. For a locally q.f.d. module , there exists a module such that is weakly injective in , for any . Similarly, if is projective and right perfect in , then there exists a module such that is weakly projective in , for any . Consequently, over a right perfect ring every module is a direct summand of a weakly projective module. For...