Let R be a ring and n, k be two non-negative integers. As an extension of several known
notions, we introduce and study (n, k)-weak cotorsion modules using the class of right R …

Let R be a ring and na fixed non-negative integer. In this paper, n-weak cotorsion modules
are introduced and studied. A right R-module N is called n-weak cotorsion module if Ext …

A ring is called $ n $-perfect ($ n\geq 0$), if every flat module has projective dimension less
or equal than $ n $. In this paper, we show that the $ n $-perfectness relate, via homological …

A ring is called n-Perfect (n≥ 0) if every flat module has projective dimension less or equal
than n. In this paper we introduce “Strong n-Perfect rings” which is in some way a …

Let $ R $ be a ring, $ S $ a multiplicative subset of $ R $. An $ R $-module $ M $ is said to
be $ u $-$ S $-flat ($ u $-always abbreviates uniformly) if $\Tor^ R_1 (M, N) $ is $ u $-$ S …

Let R be a ring, na fixed non-negative integer and ℱ ℐ n (ℱ n) the class of all right (left) R-
modules of FP-injective (flat) dimension at most n. We prove that (is a perfect cotorsion …

Let R be a ring and m, n two fixed positive integers. In this article, R is defined to be left
slightly (m, n)-coherent if each n-generated submodule of the left R-module Rm is (m, n) …

Several authors have been interested in cotorsion theories. Among these theories we figure
the pairs $(\mathcal P_n,\mathcal P_n^{\perp}) $, where $\mathcal P_n $ designates the set …

Let $ R $ be a commutative ring, and let $ S $ be a multiplicative subset of $ R $. In this
paper, we investigate the notion of $ S $-cotorsion modules. An $ R $-module $ C $ is called …

Let C be a semidualizing R-module, where R is a commutative ring. We first introduce the
definition of C-cotorsion modules, and obtain the properties of C-cotorsion modules. As …