Novi Sad Journal of Mathematics, cilt.43, sa.1, ss.41-49, 2013 (Scopus)
Let R be an arbitrary ring with identity and M a right R-module with S = EndR(M). In this paper, we introduce a class of modules that is a generalization of principally projective (or simply p.p.) rings and Baer modules. The module M is called endo-principally projective (or simply endo-p.p.) if for any m ∈ M, lS(m) = Se for some e2 = e ∈ S. For an endo-p.p. module M, we prove that M is endo-rigid (resp., endo-reduced, endo-symmetric, endo-semicommutative) if and only if the endomorphism ring S is rigid (resp., reduced, symmetric, semicommutative), and we also prove that the module M is endo-rigid if and only if M is endo-reduced if and only if M is endo-symmetric if and only if M is endo-semicommutative if and only if M is abelian. Among others we show that if M is abelian, then every direct summand of an endo-p.p. module is also endo-p.p.