Extriangulated length categories: torsion classes and $τ$-tilting theory

Fuente: arXiv
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Main Authors: Wang, Li, Wei, Jiaqun, Zhang, Haicheng, Zhou, Panyue
Format: Preprint
Published: 2025
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_version_ 1866918019809148928
author Wang, Li
Wei, Jiaqun
Zhang, Haicheng
Zhou, Panyue
author_facet Wang, Li
Wei, Jiaqun
Zhang, Haicheng
Zhou, Panyue
contents This paper introduces the notion of extriangulated length categories, whose prototypical examples include abelian length categories and bounded derived categories of finite dimensional algebras with finite global dimension. We prove that an extriangulated category $\mathcal{A}$ is a length category if and only if $\mathcal{A}$ admits a simple-minded system. Subsequently, we study the partially ordered set ${\rm tor}_Θ(\mathcal{A})$ of torsion classes in an extriangulated length category $(\mathcal{A},Θ)$ from the perspective of lattice theory. It is shown that ${\rm tor}_Θ(\mathcal{A})$ forms a complete lattice, which is further proved to be completely semidistributive and algebraic. Moreover, we describe the arrows in the Hasse quiver of ${\rm tor}_Θ(\mathcal{A})$ using brick labeling. Finally, we introduce the concepts of support torsion classes and support $τ$-tilting subcategories in extriangulated length categories and establish a bijection between these two notions, thereby generalizing the Adachi-Iyama-Reiten bijection for functorially finite torsion classes.
format Preprint
id arxiv_https___arxiv_org_abs_2502_07367
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extriangulated length categories: torsion classes and $τ$-tilting theory
Wang, Li
Wei, Jiaqun
Zhang, Haicheng
Zhou, Panyue
Representation Theory
Category Theory
This paper introduces the notion of extriangulated length categories, whose prototypical examples include abelian length categories and bounded derived categories of finite dimensional algebras with finite global dimension. We prove that an extriangulated category $\mathcal{A}$ is a length category if and only if $\mathcal{A}$ admits a simple-minded system. Subsequently, we study the partially ordered set ${\rm tor}_Θ(\mathcal{A})$ of torsion classes in an extriangulated length category $(\mathcal{A},Θ)$ from the perspective of lattice theory. It is shown that ${\rm tor}_Θ(\mathcal{A})$ forms a complete lattice, which is further proved to be completely semidistributive and algebraic. Moreover, we describe the arrows in the Hasse quiver of ${\rm tor}_Θ(\mathcal{A})$ using brick labeling. Finally, we introduce the concepts of support torsion classes and support $τ$-tilting subcategories in extriangulated length categories and establish a bijection between these two notions, thereby generalizing the Adachi-Iyama-Reiten bijection for functorially finite torsion classes.
title Extriangulated length categories: torsion classes and $τ$-tilting theory
topic Representation Theory
Category Theory
url https://arxiv.org/abs/2502.07367