Let R be a ring. A left R-module M (resp. right R-module N) is called singly injective (resp.
singly flat) if Ext1 (F/C, M)= 0 (resp. Tor1 (N, F/C)= 0) for any cyclic submodule C of any …

In this study, the concept of m-projective modules is introduced. A right R-module M is said
to be m-projective if Ext (M, N)= 0 for any m-injective right R-module N. We prove that every …

The injective hull of a module M can be characterized as a homomorphism f: M~ E (with E an
injective module) such that for each homomorphism g: M--* E'with E'injective, there exists a …

Let E be an injectively resolving subcategory of le R-modules. A le R-module M (resp. right
R-module N) is called E-injective (resp. E-at) if ExtR (G, M)=(resp. TorR (N, G)=) for any G∈ …

In the present paper, modules which are subisomorphic (in the sense of Goldie) to their pure-
injective envelopes are studied. These modules will be called almost pure-injective …

In this paper, we introduce the notion of fpn-injective and fpn-flat modules, and investigate
their properties. In particular, we prove that every left R-module has an fpn-injective cover …

A ring R is called left FGF (resp. CF) if every finitely generated (resp. cyclic) left R-module
embeds in a free module. In this paper we give new partial affirmative answers to two open …

The subjectivity domain of a module allows us to evaluate how close (or far) a module is
from being injective. In this paper, we consider three families of rings characterized by their …

n-FLAT AND n-FP-INJECTIVE MODULES 1. Introduction We use R-Mod (resp., Mod-R) to
denote the category of all left (resp., right) Page 1 Czechoslovak Mathematical Journal, 61 (136) …