Let R be an arbitrary ring and let (−)+= HomZ (−, Q/Z), where Z is the ring of integers and Q is
the ring of rational numbers. Let C be a subcategory of left R-modules and D a subcategory …

In this paper, we introduce and study UJ-modules, that is modules M for which their
endomorphism rings EM are right UJ. We show, in particular, that:(1) if M is a left UJ-module …

Let M be a right R-module with endomorphism ring S. We study the left (m, n)-coherence of
S. It is shown that S is a left (m, n)-coherent ring if and only if the left annihilator ann M n …

A module M is said to be weakly N-projective if it has a projective cover π: P (M)↠ M and for
each homomorphism: P (M)→ N there exists an epimorphism σ: P (M)↠ M such that (kerσ) …

The aim of this paper is to prove that the study of lifting and weak lifting modules over
commutative noetherian rings reduces to the case of coatomic modules, radical artinian …

Let $ R $ be a commutative ring and let $ S $ be an $ R $-algebra. It is well-known that if $ N
$ is an injective $ R $-module, then $\operatorname {Hom} _R (S, N) $ is an injective $ S …

A module M over a ring R is called automorphism-invariant if M is invariant under
automorphisms of its injective hull E (M) and M is called co-Hopfian if each injective …

抄録< p> A module M is said to be generalized N-projective (or N-dual ojective) if, for any
epimorphism g: N→ X and any homomorphism f: M→ X, there exist decompositions M= M …

Abstract Motivated by [1], we study on\tau-lifting modules (rings) and\tau-semiperfect
modules (rings) for a preradical\tau and give some equivalent conditions. We prove that; i) if …

In the previous no. te [7], we characterized" weakly" M-projective modules over a left PF ring.
In the present note, we study another type of" weakly" M-projective modules with a finiteness …