Cohomological support varieties for monomial ideals

Fuente: arXiv
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Main Authors: Fagerstrom, Kara, Faur, Julianne, Katz, Benjamin, Sundaram, Kesavan Mohana, Stern, Stephen, Watson, Ryan
Format: Preprint
Published: 2026
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author Fagerstrom, Kara
Faur, Julianne
Katz, Benjamin
Sundaram, Kesavan Mohana
Stern, Stephen
Watson, Ryan
author_facet Fagerstrom, Kara
Faur, Julianne
Katz, Benjamin
Sundaram, Kesavan Mohana
Stern, Stephen
Watson, Ryan
contents Let $R$ be a local or positively graded ring with a regular presentation $R \cong Q/I$ where $I$ is a monomial ideal generated by $n$ elements on a regular sequence. In Briggs-Grifo-Pollitz (2025), the authors classify the cohomological support varieties $\mathcal{V}_R(R)$ for $n \leqslant 5$. In this paper we extend their results to classify the varieties that can occur as $\mathcal{V}_R(R)$ for $n=6$. Moreover, we provide two families of rings, one realizing cohomological support varieties of unbounded codimension, the other realizing an unbounded number of components. Finally, we answer a question of Gintz (2026) about the varieties that occur as $\mathcal{V}_R(R)$ where $I$ is given by the edge ideal of a cycle.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29103
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Cohomological support varieties for monomial ideals
Fagerstrom, Kara
Faur, Julianne
Katz, Benjamin
Sundaram, Kesavan Mohana
Stern, Stephen
Watson, Ryan
Commutative Algebra
Combinatorics
13D99 (Primary) 05E40 (Secondary)
Let $R$ be a local or positively graded ring with a regular presentation $R \cong Q/I$ where $I$ is a monomial ideal generated by $n$ elements on a regular sequence. In Briggs-Grifo-Pollitz (2025), the authors classify the cohomological support varieties $\mathcal{V}_R(R)$ for $n \leqslant 5$. In this paper we extend their results to classify the varieties that can occur as $\mathcal{V}_R(R)$ for $n=6$. Moreover, we provide two families of rings, one realizing cohomological support varieties of unbounded codimension, the other realizing an unbounded number of components. Finally, we answer a question of Gintz (2026) about the varieties that occur as $\mathcal{V}_R(R)$ where $I$ is given by the edge ideal of a cycle.
title Cohomological support varieties for monomial ideals
topic Commutative Algebra
Combinatorics
13D99 (Primary) 05E40 (Secondary)
url https://arxiv.org/abs/2605.29103