Characterizing Multigraded Regularity and Virtual Resolutions on Products of Projective Spaces

Fuente: arXiv
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Main Authors: Bruce, Juliette, Heller, Lauren Cranton, Sayrafi, Mahrud
Format: Preprint
Published: 2021
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author Bruce, Juliette
Heller, Lauren Cranton
Sayrafi, Mahrud
author_facet Bruce, Juliette
Heller, Lauren Cranton
Sayrafi, Mahrud
contents We explore the relationship between multigraded Castelnuovo--Mumford regularity, truncations, Betti numbers, and virtual resolutions on a product of projective spaces $X$. After proving a uniqueness theorem for certain virtual resolutions, we show that the multigraded regularity region of a module $M$ is determined by the minimal graded free resolutions of the truncations $M_{\geq\mathbf d}$ for $\mathbf d\in\operatorname{Pic} X$. Further, by relating the minimal graded free resolutions of $M$ and $M_{\geq\mathbf d}$ we provide a new bound on multigraded regularity of $M$ in terms of its Betti numbers. Using this characterization of regularity and this bound we also compute the multigraded Castelnuovo--Mumford regularity for a wide class of complete intersections in products of projective spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2110_10705
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Characterizing Multigraded Regularity and Virtual Resolutions on Products of Projective Spaces
Bruce, Juliette
Heller, Lauren Cranton
Sayrafi, Mahrud
Commutative Algebra
Algebraic Geometry
13D02, 14M25
We explore the relationship between multigraded Castelnuovo--Mumford regularity, truncations, Betti numbers, and virtual resolutions on a product of projective spaces $X$. After proving a uniqueness theorem for certain virtual resolutions, we show that the multigraded regularity region of a module $M$ is determined by the minimal graded free resolutions of the truncations $M_{\geq\mathbf d}$ for $\mathbf d\in\operatorname{Pic} X$. Further, by relating the minimal graded free resolutions of $M$ and $M_{\geq\mathbf d}$ we provide a new bound on multigraded regularity of $M$ in terms of its Betti numbers. Using this characterization of regularity and this bound we also compute the multigraded Castelnuovo--Mumford regularity for a wide class of complete intersections in products of projective spaces.
title Characterizing Multigraded Regularity and Virtual Resolutions on Products of Projective Spaces
topic Commutative Algebra
Algebraic Geometry
13D02, 14M25
url https://arxiv.org/abs/2110.10705