On the class of Benson's cofibrant modules

Fuente: arXiv
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Main Authors: Emmanouil, Ioannis, Ren, Wei
Format: Preprint
Published: 2025
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author Emmanouil, Ioannis
Ren, Wei
author_facet Emmanouil, Ioannis
Ren, Wei
contents 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 $kG$-modules. It follows that the class of Gorenstein projective $kG$-modules is special precovering in the category of $kG$-modules, if $G$ is contained in the class ${\scriptstyle{\bf LH}}\mathfrak{F}$ of hierarchically decomposable groups defined by Kropholler in [20] and $k$ has finite weak global dimension. It also follows that the obstruction to the equality between the classes of cofibrant and Gorenstein projective $kG$-modules can be described, over any group algebra $kG$, in terms of a suitable subcategory of the stable category of Gorenstein projective $kG$-modules.
format Preprint
id arxiv_https___arxiv_org_abs_2503_04284
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the class of Benson's cofibrant modules
Emmanouil, Ioannis
Ren, Wei
K-Theory and Homology
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 $kG$-modules. It follows that the class of Gorenstein projective $kG$-modules is special precovering in the category of $kG$-modules, if $G$ is contained in the class ${\scriptstyle{\bf LH}}\mathfrak{F}$ of hierarchically decomposable groups defined by Kropholler in [20] and $k$ has finite weak global dimension. It also follows that the obstruction to the equality between the classes of cofibrant and Gorenstein projective $kG$-modules can be described, over any group algebra $kG$, in terms of a suitable subcategory of the stable category of Gorenstein projective $kG$-modules.
title On the class of Benson's cofibrant modules
topic K-Theory and Homology
url https://arxiv.org/abs/2503.04284