Nonexistence of Negative Curves

Abstract Let $X$ be the blowup of a weighted projective plane ${\mathbb {P}}(a,b,c)$ at a general point. The Kleiman–Mori cone of $X$ is two-dimensional with one ray generated by the class of the exceptional curve $E$. It is not known if the second extremal ray is always generated by the class of a...

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Bibliographic Details
Published in:International mathematics research notices Vol. 2023; no. 16; pp. 14368 - 14400
Main Authors: González Anaya, Javier, González, José Luis, Karu, Kalle
Format: Journal Article
Language:English
Published: Oxford University Press 01-08-2023
Online Access:Get full text
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Summary:Abstract Let $X$ be the blowup of a weighted projective plane ${\mathbb {P}}(a,b,c)$ at a general point. The Kleiman–Mori cone of $X$ is two-dimensional with one ray generated by the class of the exceptional curve $E$. It is not known if the second extremal ray is always generated by the class of a curve. We construct an infinite family of projective toric surfaces of Picard number one such that their blowups $X$ at a general point have half-open Kleiman–Mori cones: there is no negative curve generating the other boundary ray of the cone.
ISSN:1073-7928
1687-0247
DOI:10.1093/imrn/rnac355