Torsion points and concurrent exceptional curves on del Pezzo surfaces of degree one
Abstract
The blow-up of the anticanonical base point on a del Pezzo surface of degree 1 gives rise to a rational elliptic surface with only irreducible fibers. The sections of minimal height of are in correspondence with the exceptional curves on . A natural question arises when studying the configuration of these curves: if a point on is contained in 'many' exceptional curves, it is torsion on its fiber on ? In 2005, Kuwata proved for the analogous question on del Pezzo surfaces of degree , where there are 56 exceptional curves, that if 'many' equals or more, the answer is yes. In this paper, we prove that for del Pezzo surfaces of degree 1, the answer is yes if 'many' equals or more. Moreover, we give counterexamples where a \textsl{non}-torsion point lies in the intersection of exceptional curves. We give partial results for the still open case of 8 intersecting exceptional curves.
Keywords
Cite
@article{arxiv.2210.11659,
title = {Torsion points and concurrent exceptional curves on del Pezzo surfaces of degree one},
author = {Julie Desjardins and Rosa Winter},
journal= {arXiv preprint arXiv:2210.11659},
year = {2025}
}
Comments
14 pages, published in CBM