Purity, ascent, and periodicity for Gorenstein flat cotorsion modules

Fuente: arXiv
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Autore principale: Bird, Isaac
Natura: Preprint
Pubblicazione: 2021
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author Bird, Isaac
author_facet Bird, Isaac
contents We investigate purity within the Frobenius category of Gorenstein flat cotorsion modules, which can be seen as an infinitely generated analogue of the Frobenius category of Gorenstein projective objects. As such, the associated stable category can be viewed as an alternative approach to a big singularity category, which is equivalent to Krause's when the ring is Gorenstein. We study the pure structure of the stable category, and show it is fundamentally related to the pure structure of the Gorenstein flat modules. Following that, we give conditions for extension of scalars to preserve Gorenstein flat cotorsion modules. In this case, one obtains an induced triangulated functor on the stable categories. We show that under mild conditions that these functors preserve the pure structure, both on the triangulated and module category level. Along the way, we consider particular phenomena over commutative rings, the cumulation of which is an extension of Knörrer periodicity, giving a triangulated equivalence between Krause's big singularity categories for a complete hypersurface singularity and its twofold double-branched cover.
format Preprint
id arxiv_https___arxiv_org_abs_2108_08135
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Purity, ascent, and periodicity for Gorenstein flat cotorsion modules
Bird, Isaac
Representation Theory
Commutative Algebra
16E30, 16G80, 18E45, 18G25, 13D07
We investigate purity within the Frobenius category of Gorenstein flat cotorsion modules, which can be seen as an infinitely generated analogue of the Frobenius category of Gorenstein projective objects. As such, the associated stable category can be viewed as an alternative approach to a big singularity category, which is equivalent to Krause's when the ring is Gorenstein. We study the pure structure of the stable category, and show it is fundamentally related to the pure structure of the Gorenstein flat modules. Following that, we give conditions for extension of scalars to preserve Gorenstein flat cotorsion modules. In this case, one obtains an induced triangulated functor on the stable categories. We show that under mild conditions that these functors preserve the pure structure, both on the triangulated and module category level. Along the way, we consider particular phenomena over commutative rings, the cumulation of which is an extension of Knörrer periodicity, giving a triangulated equivalence between Krause's big singularity categories for a complete hypersurface singularity and its twofold double-branched cover.
title Purity, ascent, and periodicity for Gorenstein flat cotorsion modules
topic Representation Theory
Commutative Algebra
16E30, 16G80, 18E45, 18G25, 13D07
url https://arxiv.org/abs/2108.08135