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Related papers: Intersection of complete cotorsion pairs

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We show a cotorsion pair cogenerated by a class is complete under suitable conditions in an arbitrary exact category using the generalized small object argument given by Chorny. This recovers Saor\'in and \v{S}\v{t}ov\'{i}\v{c}ek's…

Representation Theory · Mathematics 2018-03-08 Zhi-Wei Li

We apply the theory of cotorsion pairs to study closure properties of classes of modules with finite projective dimension with respect to direct limit operations and to filtrations. We also prove that if the ring is an order in an…

Rings and Algebras · Mathematics 2011-11-10 Silvana Bazzoni , Dolors Herbera

Let $R\to A$ be a homomorphism of associative rings, and let $(\mathcal F,\mathcal C)$ be a hereditary complete cotorsion pair in $R\mathsf{-Mod}$. Let $(\mathcal F_A,\mathcal C_A)$ be the cotorsion pair in $A\mathsf{-Mod}$ in which…

Rings and Algebras · Mathematics 2023-04-19 Leonid Positselski

We study homological and homotopical aspects of Gorenstein flat modules over a ring with respect to a duality pair $(\mathcal{L,A})$. These modules are defined as cycles of exact chain complexes with components in $\mathcal{L}$ which remain…

Representation Theory · Mathematics 2024-03-13 Víctor Becerril , Marco A. Pérez

The existence of the Gorenstein projective precovers over $R$ an arbitrary ring, as well as the completeness of the Gorenstein projective cotorsion pair $(\mathcal{GP},\mathcal{GP}^{\perp})$, are open questions. In this paper, we provide…

Rings and Algebras · Mathematics 2026-02-25 Víctor Becerril

We study the notions of $n$-hereditary rings and its connection to the classes of finitely $n$-presented modules, FP$_n$-injective modules, FP$_n$-flat modules and $n$-coherent rings. We give characterizations of $n$-hereditary rings in…

Rings and Algebras · Mathematics 2018-08-13 Daniel Bravo , Carlos E. Parra

In contrast with the Hovey correspondence of abelian model structures from two compatible complete cotorsion pairs, Beligiannis and Reiten give a construction of model structures on abelian categories from one hereditary complete cotorsion…

Category Theory · Mathematics 2025-03-18 Jian Cui , Pu Zhang

We introduce the notion of a duality pair and demonstrate how the left half of such a pair is often covering and preenveloping. As an application, we generalize a result by Enochs et al. on Auslander and Bass classes, and we prove that the…

Commutative Algebra · Mathematics 2009-05-07 Henrik Holm , Peter Jorgensen

We prove that the class of Gorenstein projective modules is special precovering over any left GF-closed ring such that every Gorenstein projective module is Gorenstein flat and every Gorenstein flat module has finite Gorenstein projective…

Commutative Algebra · Mathematics 2016-01-12 Sergio Estrada , Alina Iacob , Katelyn Yeomans

For a given class of modules $\mathcal{A}$, we denote by $\widetilde{\mathcal{A}}$ the class of exact complexes $X$ having all cycles in $\mathcal{A}$, and by $dw(\mathcal{A})$ the class of complexes $Y$ with all components $Y_j$ in…

Rings and Algebras · Mathematics 2020-01-22 Sergio Estrada , Alina Iacob , Holly Zolt

We study singularity categories of exact categories with a focus on those associated to a complete hereditary cotorsion pair. As an application we identify a non-affine analogue of the singularity category of a Gorenstein local ring; with…

K-Theory and Homology · Mathematics 2022-05-06 Lars Winther Christensen , Nanqing Ding , Sergio Estrada , Jiangsheng Hu , Huanhuan Li , Peder Thompson

This paper is to study cotorsion pairs and abelian model structures on some Morita rings \ $\Lambda =\left(\begin{smallmatrix} A & {}_AN_B {}_BM_A & B\end{smallmatrix}\right)$. From cotorsion pairs $(\mathcal U, \mathcal X)$ and $(\mathcal…

Representation Theory · Mathematics 2023-12-12 Pu Zhang , Jian Cui , Shi Rong

We give a sufficient condition for the class of Gorenstein injective modules be precovering: if $R$ is right noetherian and if the class of Gorenstein injective modules, $\mathcal{GI}$, is closed under filtrations, then $\mathcal{GI}$ is…

Commutative Algebra · Mathematics 2013-01-25 Edgar Enochs , Sergio Estrada , Alina Iacob

We prove that every Grothendieck topology induces a hereditary torsion pair in the category of presheaves of modules on a ringed site, and obtain a homological characterization of sheaves of modules: a presheaf of modules is a sheaf of…

Representation Theory · Mathematics 2025-07-30 Zhenxing Di , Liping Li , Li Liang

We give a simultaneous generalization of exact categories and triangulated categories, which is suitable for considering cotorsion pairs, and which we call extriangulated categories. Extension-closed, full subcategories of triangulated…

Category Theory · Mathematics 2019-04-29 Hiroyuki Nakaoka , Yann Palu

The existence of the Gorenstein projective precovers over arbitrary rings is an open question. In this paper, we make use of three diferent techniques addressing intrinsic and homological properties of several classes of relative Gorenstein…

Rings and Algebras · Mathematics 2025-10-08 Víctor Becerril

For the module category of an Artin algebra, we generalize the notion of torsion pairs to ideal torsion pairs. Instead of full subcategories of modules, ideals of morphisms of the ambient category are considered. We characterize the…

Representation Theory · Mathematics 2026-02-25 Kevin Schlegel

In this paper, we examine the class of cofibrant modules over a group algebra $kG$, that were defined by Benson in [2]. We show that this class is always the left-hand side of a complete hereditary cotorsion pair in the category of…

K-Theory and Homology · Mathematics 2025-03-07 Ioannis Emmanouil , Wei Ren

By the Telescope Conjecture for Module Categories, we mean the following claim: "Let R be any ring and (A, B) be a hereditary cotorsion pair in Mod-R with A and B closed under direct limits. Then (A, B) is of finite type." We prove a…

Rings and Algebras · Mathematics 2008-09-16 Jan Saroch , Jan Stovicek

Codimension 2 complete intersections in P^N have a natural parameter space \bar{H}: a projective bundle over a projective space given by the choice of the lower degree equation and of the higher degree equation up to a multiple of the…

Algebraic Geometry · Mathematics 2026-01-21 Olivier Benoist