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 …

R is a ring and M is a right R-module for which Rl={m∊ M| mR= 0} is the zero submodule. Let
and be the injective hull and the quasi-injective hull of M respectively. Then where [1]. The …

Throughout, all rings R are associative with identity, and all inodules are unitary right R-
modules. By a class K of modules we inean K is a collection of nlodules such that K is closed …

Let R be a ring. An R-module X is called c-injective if, for every closed submodule L of every
R-module M, every homomorphism from L to X lifts to M. It is proved that if R is a Dedekind …

The restricted injective envelopes with respect to various types of preradicals have been
studied by many authors (see eg [2],[6],[8],[10]). In the second paragraph we shall dualize …

PM Cohn [6] has defined the notion of a pure submodule. Subsequently CP Walker [21], B.
StenstrSm [19] and DP Choudhury and K. Tewari [5] have introduced notions of copurity as …

Let R be a left Artinian ring, U a left R-module and T= End (RU). From a well known theorem
of Morita duality the following conditions are equivalent (see [II, il11,[W:(i) There exists a …

Let R be a ring and M a right R-module. Let σ [M] be the full subcategory of Mod-R
subgenerated by M. An M-natural class 𝒦 is a subclass of σ [M] closed under submodules …

Let R be a ring with identity element and M be a unitary left R-module. M is called quasi-
injective if every element in Hom^ Af, M) for any R-module N in M is extened to an element in …

QUASI-INJECTIVE AND PSEUDO-INFECTIVE MODULES Page 1 Canad. Math. Bull. Vol. 18
(3), 1975 QUASI-INJECTIVE AND PSEUDO-INFECTIVE MODULES BY SK JAIN AND SURJEET …