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 …

Given a ring $ R $, two classes $\mathcal A $ and $\mathcal B $ of $ R $-modules are said
to form a cotorsion pair $(\mathcal A,\mathcal B) $ in $\operatorname {Mod} R $ if $\mathcal …

Chapter 19 The Cotorsion Dimension of Modules and Rings Lixin Mao Department of Basic
Courses, Nanjing Institute of Technology, Nanjing 210013, Peoples Republic of China …

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 …

We introduce the concepts of (n, d)-injective and (n, d)-flat as generalizations of injective, flat
modules and homological dimensions, and use them to characterize right n-coherent rings …

Let R be a ring. We define a dimension, called P-cotorsion dimension, for modules and
rings. The aim of this article is to investigate P-cotorsion dimensions of modules and rings …

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 …

R is called a right ${\Pi}-coherent $ ring in case every finitely generated torsion less right R-
module is finitely presented. In this paper, we define a dimension for rings, called ${\Pi} …

Following, a ring R is called right almost-perfect if every flat right R-module is projective
relative to R. In this article, we continue the study of these rings and will find some new …

Let R be a left and right Noetherian ring. We introduce the notion of the torsionfree
dimension of finitely generated R-modules. For any n 0, we prove that R is a Gorenstein ring …