Betti numbers and linear covers of points

Fuente: arXiv
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Hauptverfasser: Dao, Hailong, Lund, Ben, Suresh-Babu, Sreehari
Format: Preprint
Veröffentlicht: 2024
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author Dao, Hailong
Lund, Ben
Suresh-Babu, Sreehari
author_facet Dao, Hailong
Lund, Ben
Suresh-Babu, Sreehari
contents We prove that for a finite set of points $X$ in the projective $n$-space over any field, the Betti number $β_{n,n+1}$ of the coordinate ring of $X$ is non-zero if and only if $X$ lies on the union of two planes whose sum of dimension is less than $n$. Our proof is direct and short, and the inductive step rests on a combinatorial statement that works over matroids.
format Preprint
id arxiv_https___arxiv_org_abs_2408_14064
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Betti numbers and linear covers of points
Dao, Hailong
Lund, Ben
Suresh-Babu, Sreehari
Commutative Algebra
Algebraic Geometry
Combinatorics
We prove that for a finite set of points $X$ in the projective $n$-space over any field, the Betti number $β_{n,n+1}$ of the coordinate ring of $X$ is non-zero if and only if $X$ lies on the union of two planes whose sum of dimension is less than $n$. Our proof is direct and short, and the inductive step rests on a combinatorial statement that works over matroids.
title Betti numbers and linear covers of points
topic Commutative Algebra
Algebraic Geometry
Combinatorics
url https://arxiv.org/abs/2408.14064