The purpose of this paper is to initiate the study of improjective modules. A module X is im-
projective if given any epimorphism/: B-> A and any homomorphism/: X-> A, there exists a …

The object of this paper is to study the relationship between certain projective modules and
their endomorphism rings. Specifically, the basic problem is to describe the projective …

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) …

Let R be a ring and M a fixed R-module. An R-module Q is called M-injective if, given a
monomorphism C $ of an R-module N into M, every homomorphism: N-+ Q can be extended …

ABSTRACT A module M Is said to be weakly projective If and only If It has a projective cover
11": P (M)--+ M and every map from P (M) Into a finitely generated (free) module can be …

The purpose of this dissertation is to study weakly projective modules, a concept dual to that
of weakly injective modules. Let M and N be right R-modules. M is called weakly N …

Let RP be a projective R-module which is not finitely generated. Let E= End R (P). This
paper examines the structure of P as an E-module and relations between right ideals of R …

A ring $ R $ is regular [completely reducible] if and only if the character module of every left
$ R $-module is quasi-injective [quasiprojective]. Submodules of quasiprojective left $ R …

Cukerman [2], Shanny [5], and Ware [7] have shown that a ring R is Artin semisimple if and
only if R has a nonfinitely generated free module with regular endomorphism ring. This …

Sandomierski (Proc. AMS 21 (1969), 205–207) has proved that a ring is semiperfect if and
only if every simple module has a projective cover. This is generalized to semiperfect …