On the structure of open del Pezzo surfaces

Fuente: arXiv
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Autori principali: Palka, Karol, Pełka, Tomasz
Natura: Preprint
Pubblicazione: 2024
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author Palka, Karol
Pełka, Tomasz
author_facet Palka, Karol
Pełka, Tomasz
contents Let $(X,D)$ be an open log del Pezzo surface of rank one, that is, $X$ is a normal projective surface of Picard rank one, the boundary $D$ is a reduced nonzero divisor on $X$, and the anti-log canonical divisor $-(K_X+D)$ is ample. We show that, up to well described exceptions in characteristics 2, 3 and 5, the smooth part of $X\setminus D$ admits an $\mathbb{A}^1$- or an $\mathbb{A}^{1}_{*}$-fibration, which extends to a $\mathbb{P}^1$-fibration of the minimal log resolution of $(X,D)$. In characteristic 0 this improves a well-known structure theorem of Miyanishi-Tsunoda. Within the proof, we classify rational anti-canonical curves contained in smooth loci of canonical del Pezzo surfaces of rank one.
format Preprint
id arxiv_https___arxiv_org_abs_2412_07458
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the structure of open del Pezzo surfaces
Palka, Karol
Pełka, Tomasz
Algebraic Geometry
14J10 (Primary) 14D06, 14J45, 14R05 (Secondary)
Let $(X,D)$ be an open log del Pezzo surface of rank one, that is, $X$ is a normal projective surface of Picard rank one, the boundary $D$ is a reduced nonzero divisor on $X$, and the anti-log canonical divisor $-(K_X+D)$ is ample. We show that, up to well described exceptions in characteristics 2, 3 and 5, the smooth part of $X\setminus D$ admits an $\mathbb{A}^1$- or an $\mathbb{A}^{1}_{*}$-fibration, which extends to a $\mathbb{P}^1$-fibration of the minimal log resolution of $(X,D)$. In characteristic 0 this improves a well-known structure theorem of Miyanishi-Tsunoda. Within the proof, we classify rational anti-canonical curves contained in smooth loci of canonical del Pezzo surfaces of rank one.
title On the structure of open del Pezzo surfaces
topic Algebraic Geometry
14J10 (Primary) 14D06, 14J45, 14R05 (Secondary)
url https://arxiv.org/abs/2412.07458