Let dwI denote the class of#-injective complexes of left R-modules (ie, complexes of injective
left R-modules). We prove that over left noetherian rings R, the pair (⊥(dwI), dwI) is a perfect …

In this article, FP-injective complexes are introduced and studied. We prove that (⊥ ℱℐ, ℱℐ)
is a hereditary cotorsion theory if and only if R is a left coherent ring, where ℱℐ denotes the …

Let R be a ring. A right R-module C is called cotorsion if for any flat right R-module biF. In
this paper, we first give some results on cotorsion envelopes that are analogous to those on …

Let R be a ring. A right R-module C is called a cotorsion module if Ext1R (F, C)= 0 for any flat
right R-module F. In this paper, we first characterize those rings satisfying the condition that …

In this paper we prove that the extension of pure injective module is pure injective if and only
if the cotorsion envelope and the pure injective envelope of any R-module M are isomorphic …

Let R be a ring. A right R-module M is called f-projective if Ext1 (M, N)= 0 for any f-injective
right R-module N. We prove that (F-proj, F-inj) is a complete cotorsion theory, where F-proj …

Let ℒ be a class of right modules, whenever covers and envelopes exist, we show that if ℒ is
closed under extensions and direct summands, then P (ℒ), the class of all ℒ-projective right …

In this paper, we introduce the notion of cofinitely injective modules and study their
properties over special types of rings. We define a right R‐module M to be cofinitely injective …

A submodule N of a module M is called S-closed (in M) if M/N is nonsingular. It is well-known
that the class Closed of short exact sequences determined by closed submodules is a …

For a ring R, there are classical facts that R is right Noetherian if and only if every direct sum
of injective right R-modules is injective, and R is right Noetherian if and only if every …