Abstract

Let R be a ring and M a right R-module with S=End(MR). The module M is called almost principally quasi-injective (or APQ-injective for short) if, for any m∈M, there exists an S-submodule Xm of M such that lMrR(m)=Sm⊕Xm. The module M is called almost quasiprincipally injective (or AQP-injective for short) if, for any s∈S, there exists a left ideal Xs of S such that lS(Ker(s))=Ss⊕Xs. In this paper, we give some characterizations and properties of the two classes of modules. Some results on principally quasi-injective modules and quasiprincipally injective modules are extended to these modules, respectively. Specially in the case RR, we obtain some results on AP-injective rings as corollaries.