Cox rings of nef anticanonical rational surfaces

Fuente: arXiv
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Main Authors: Artebani, Michela, Garbayo, Sofía Pérez
Format: Preprint
Published: 2024
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author Artebani, Michela
Garbayo, Sofía Pérez
author_facet Artebani, Michela
Garbayo, Sofía Pérez
contents This paper deals with the problem of computing a generating set for the Cox ring $R(X)$ of a smooth projective rational surface $X$ with nef anticanonical class. In case $R(X)$ is finitely generated, we show that the degrees of its generators are either classes of negative curves, elements of the Hilbert basis of the nef cone or certain ample classes of anticanonical degree one, which only appear when $X$ is a rational elliptic surface of Halphen index $m>2$. Moreover, we partially characterize which elements of the Hilbert basis of the nef cone are irredundant for generating $R(X)$. We apply this result to compute explicit minimal generating sets for Cox rings of some rational elliptic surfaces of Halphen index $>1$.
format Preprint
id arxiv_https___arxiv_org_abs_2403_09945
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Cox rings of nef anticanonical rational surfaces
Artebani, Michela
Garbayo, Sofía Pérez
Algebraic Geometry
14J26, 14C20
This paper deals with the problem of computing a generating set for the Cox ring $R(X)$ of a smooth projective rational surface $X$ with nef anticanonical class. In case $R(X)$ is finitely generated, we show that the degrees of its generators are either classes of negative curves, elements of the Hilbert basis of the nef cone or certain ample classes of anticanonical degree one, which only appear when $X$ is a rational elliptic surface of Halphen index $m>2$. Moreover, we partially characterize which elements of the Hilbert basis of the nef cone are irredundant for generating $R(X)$. We apply this result to compute explicit minimal generating sets for Cox rings of some rational elliptic surfaces of Halphen index $>1$.
title Cox rings of nef anticanonical rational surfaces
topic Algebraic Geometry
14J26, 14C20
url https://arxiv.org/abs/2403.09945