In this paper, we investigate the notions of $\mathcal {X}^\bot $-projective, $\mathcal {X} $-
injective and $\mathcal {X} $-flat modules and give some characterizations of these …

In this paper, we investigate the notions of X⊥‐projective, X‐injective, and X‐flat modules
and give some characterizations of these modules, where X is a class of left modules. We …

In this paper, we investigate the notions of UX-projective, X-injective and X-flat modules and
give their characterizations, where X is the class of left R-modules. We prove the class of all …

We denote by $\mathcal {W} $ the class of all pure projective modules. Present article we
investigate $\mathcal {W} $-injective modules and these modules are defined via the …

Let $ M $ be a left $ R-$ module and $\pazocal {A}=\{A\} _ {A\in\pazocal {A}} $ be a family of
some submodules of $ M $. It is introduced the classes of (strongly) $ M-\pazocal {A} …

In this paper, we introduce the concept of-flat (respectively,--injective) modules as nontrivial
generalization of flat (respectively, injective) modules. We first investigate various properties …

Let M be a module. A\delta-cover of M is an epimorphism from a module F onto M with
a\delta-small kernel. A\delta-cover is said to be a flat\delta-cover in case F is a flat module. In …

A right $ R $-module $ M $ is called $ R $-projective provided that it is projective relative to
the right $ R $-module $ R_ {R} $. This paper deals with the rings whose all nonsingular …

Let ℒ1⊇ ℒ2 be classes of right R-modules, we introduce ℒ1-covering modules and
projective modules relative to ℒ2 to characterize the relations between the existences of ℒ1 …

A right R-module M is called R-projective provided that it is projective relative to the right R-
module RR. One of the parts of this thesis deals with the rings whose all nonsingular right …