On w-copure projective modules

Let $R$ be a commutative ring. An $R$-module $M$ is said to be $w$-split if Ext$_{R}^1(M,N)$ is a GV-torsion $R$-module for all $R$-modules $N$. It is known that every projective module is $w$-split, but the converse is not true in general. In this paper, we study the w-split dimension of a flat module. To do so, we introduce and study the so-called $w$-copure (resp., strongly $w$-copure) projective modules which is in some way a generalization of the notion of copure (resp., strongly copure) projective modules. An $R$-module $M$ is said to be $w$-copure projective (resp., strongly $w$-copure projective) if Ext$_{R}^1(M,N)$ (resp., Ext$_{R}^n(M,N)$) is a GV-torsion $R$-module for all flat $R$-modules $N$ and any $n\geq1$.Comment: 13 page

On τq\tau_q-weak global dimensions of commuative rings

In this paper, the $\tau_q$-weak global dimension $\tau_q$-\cwd$(R)$ of a commutative ring $R$ is introduced. Rings with $\tau_q$-weak global dimension equal to $0$ are studied in terms of homologies, direct products, polynomial extensions and amalgamations. Besides, we investigate the $\tau_q$-weak global dimensions of polynomial rings.Comment: arXiv admin note: text overlap with arXiv:2111.03417, arXiv:2302.0456

S-FP-Projective Modules and Dimensions

Let R be a ring and let S be a multiplicative subset of R. An R-module M is said to be a u-S-absolutely pure module if ExtR1N,M is u-S-torsion for any finitely presented R-module N. This paper introduces and studies the notion of S-FP-projective modules, which extends the classical notion of FP-projective modules. An R-module M is called an S-FP-projective module if ExtR1M,N=0 for any u-S-absolutely pure R-module N. We also introduce the S-FP-projective dimension of a module and the global S-FP-projective dimension of a ring. Then, the relationship between the S-FP-projective dimension and other homological dimensions is discussed