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Related papers: On $\tau_q$-flatness and $\tau_q$-coherence

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In this note, we show that a ring $R$ is $S$-coherent if and only if every finitely presented $R$-module is $S$-coherent, providing a positive answer to a question proposed in [D. Bennis, M. El Hajoui, {\it On $S$-coherence}, J. Korean…

Commutative Algebra · Mathematics 2024-05-21 Xiaolei Zhang

We study the class of rings $R$ for which every direct sum of injective $R$-modules is cotorsion. We call them weakly $\Sigma$-cotorsion rings. The defining property might be seen as the dual of Chase's characterization of coherence in…

Rings and Algebras · Mathematics 2026-02-13 Manuel Cortés-Izurdiaga , Sergio Estrada , José Manuel Fresneda

We use the concept of a regular object with respect to another object in an arbitrary category, defined in \cite{dntd}, in order to obtain the transfer of regularity in the sense of Zelmanowitz between the categories $R-$mod and $S-$mod,…

Rings and Algebras · Mathematics 2008-03-11 Leonard Daus

Let $R$ be a commutative ring. An $R$-module $M$ is called a semi-regular $w$-flat module if $\Tor_1^R(R/I,M)$ is $\GV$-torsion for any finitely generated semi-regular ideal $I$. In this article, we show that the class of semi-regular…

Commutative Algebra · Mathematics 2023-03-07 Xiaolei Zhang

In this paper, we first study the Gorenstein projective/flat dimension of complexes of modules. The relation between the Gorenstein projective/flat dimension for complexes and that for modules are investigated. Then we study Tate, stable…

Rings and Algebras · Mathematics 2020-09-18 Li Liang

The aim of this paper is to introduce a new class of Noetherian rings of positive characteristic in terms of perfect closures and study their basic properties. If the perfect closure of a Noetherian ring is coherent, we call it an…

Commutative Algebra · Mathematics 2014-10-07 Kazuma Shimomoto

The purpose of this work is to investigate various notions of regularity from the perspective of finiteness conditions, with the ultimate goal of identifying broad classes of rings that are $\mathsf{K}_0$-regular. In this direction, we…

Rings and Algebras · Mathematics 2026-04-02 Rafael Parra

We prove coherence of relatively quasi-free algebras over noetherian rings. Chase criterion for coherence is used.

Rings and Algebras · Mathematics 2015-01-13 Alexey Bondal , Ilya Zhdanovskiy

Let $R$ by a right coherent ring and $R$-Mod denote the category of left $R$-modules. We show that there is an abelian model structure on $R$-Mod whose cofibrant objects are precisely the Gorenstein flat modules. Employing a new method for…

Rings and Algebras · Mathematics 2016-09-20 James Gillespie

Flat modules play an important role in the study of the category of modules over rings and in the characterization of some classes of rings. We study the e-flatness for semimodules introduced by the first author using his new notion of…

Rings and Algebras · Mathematics 2025-10-28 Jawad Abuhlail , Rangga Ganzar Noegraha

In this note, we give the Cohen type theorem for uniformly $S$-Noetherian modules and the Eakin-Nagata type theorem for uniformly $S$-Noetherian rings. We also solve an open question proposed by Kim and Lim [5,Question 4.10].

Commutative Algebra · Mathematics 2023-02-24 Xiaolei Zhang

A 2009 paper by Iacob and Iyengar characterizes noetherian regular rings in terms of properties of complexes of projective modules, flat modules, and injective modules. We show that the relevant properties of such complexes are equivalent…

Rings and Algebras · Mathematics 2026-01-27 Lars Winther Christensen , Sergio Estrada , Peder Thompson

Let R be a commutative ring with identity and S a multiplicative subset of R. The aim of this paper is to study the class of commutative rings in which every S-flat module is flat (resp., projective). An R-module M is said to be S-flat if…

Commutative Algebra · Mathematics 2024-03-08 Driss Bennis , Ayoub Bouziri

In this paper, we investigate the notions of almost Noetherian rings and modules. In details, we give the Cohen type theorem, Eakin-Nagata type theorem, Kaplansky type Theorem and Hilbert basis theorem and some other rings constructions for…

Commutative Algebra · Mathematics 2026-02-24 Xiaolei Zhang

This paper studies the tensor product of flat cotorsion modules. Let~$R$~and $S$ be~$k$-algebras. We prove that both~$R$-module\ $M$ and~$S$-module\ $N$ are flat cotorsion modules if and only if~$M\otimes_{k} N$ is a flat…

Rings and Algebras · Mathematics 2025-02-27 Yonggang Hu , Linyu Ma , Xintian Wang

We prove that if $R$ is a commutative Noetherian ring, then every countably generated flat $R$-module is quite flat, i.e., a direct summand of a transfinite extension of localizations of $R$ in countable multiplicative subsets. We also show…

Commutative Algebra · Mathematics 2022-06-02 Michal Hrbek , Leonid Positselski , Alexander Slávik

In this paper several characterizations of semi-compact modules are given. Among other results, we study rings whose semi-compact modules are injective. We introduce the property $\Sigma$-semi-compact for modules and we characterize the…

Commutative Algebra · Mathematics 2022-03-08 Mahmood Behboodi , François Couchot , Seyed Hossein Shojaee

We study the notion of regular ring in the sense of Vogel, which generalizes the classical notion for non-necessarily coherent rings. We build a class of groups "R" containing Waldhausen's class "Cl" in [Wald78] and study its stability…

K-Theory and Homology · Mathematics 2007-05-23 Frank Bihler

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 $S$-cotorsion if $\text{Ext}^{1}_{R}(F,C) = 0$ for every $S$-flat…

Commutative Algebra · Mathematics 2024-09-02 Driss Bennis , Ayoub Bouziri

In this article, we introduce the notion of regular fusible modules. Let $R$ be a ring with an identity and $M$ an $R$-module. An element $0\neq m\in M$ is said to be regular fusible if there exists $r\in R$, a non zero-divisor of $M$, such…

Rings and Algebras · Mathematics 2024-03-22 Osama A. Naji , Mehmet Özen , Ünsal Tekir , Suat Koç