On local rings of finite syzygy representation type

Fuente: arXiv
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Main Authors: Dey, Souvik, Kimura, Kaito, Liu, Jian, Otake, Yuya
Format: Preprint
Published: 2025
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author Dey, Souvik
Kimura, Kaito
Liu, Jian
Otake, Yuya
author_facet Dey, Souvik
Kimura, Kaito
Liu, Jian
Otake, Yuya
contents Let $R$ be a commutative Noetherian local ring. We characterize when its completion has an isolated singularity, thereby strengthening the Dao-Takahashi refinement of the Auslander-Huneke-Leuschke-Wiegand theorem. We investigate the ascent and descent of finite and countable syzygy representation type along the canonical map from $R$ to its completion. One consequence is a complete affirmative answer to Schreyer's conjecture. We explore analogues of Chen's questions in the context of finite Cohen-Macaulay representation type over Cohen-Macaulay rings. The main result in this direction shows that if $R$ is Cohen-Macaulay and there are only finitely many non-isomorphic indecomposable maximal Cohen-Macaulay modules that are locally free on the punctured spectrum, then either $R$ is a hypersurface or every Gorenstein projective module is projective; moreover, every Gorenstein projective module over the completion of $R$ is a direct sum of finite generated ones. Finally, we study dominant local rings, introduced by Takahashi, under certain finite representation type conditions, and identify a new class of virtually Gorenstein rings.
format Preprint
id arxiv_https___arxiv_org_abs_2507_17097
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On local rings of finite syzygy representation type
Dey, Souvik
Kimura, Kaito
Liu, Jian
Otake, Yuya
Commutative Algebra
Representation Theory
13C14, 13C60, 13D09, 16G60, 18G80
Let $R$ be a commutative Noetherian local ring. We characterize when its completion has an isolated singularity, thereby strengthening the Dao-Takahashi refinement of the Auslander-Huneke-Leuschke-Wiegand theorem. We investigate the ascent and descent of finite and countable syzygy representation type along the canonical map from $R$ to its completion. One consequence is a complete affirmative answer to Schreyer's conjecture. We explore analogues of Chen's questions in the context of finite Cohen-Macaulay representation type over Cohen-Macaulay rings. The main result in this direction shows that if $R$ is Cohen-Macaulay and there are only finitely many non-isomorphic indecomposable maximal Cohen-Macaulay modules that are locally free on the punctured spectrum, then either $R$ is a hypersurface or every Gorenstein projective module is projective; moreover, every Gorenstein projective module over the completion of $R$ is a direct sum of finite generated ones. Finally, we study dominant local rings, introduced by Takahashi, under certain finite representation type conditions, and identify a new class of virtually Gorenstein rings.
title On local rings of finite syzygy representation type
topic Commutative Algebra
Representation Theory
13C14, 13C60, 13D09, 16G60, 18G80
url https://arxiv.org/abs/2507.17097