English

On the Classification of K3-Surfaces with Nine Cusps

Algebraic Geometry 2007-05-23 v1

Abstract

By a K3-surface with nine cusps I mean a compact complex surface with nine isolated double points A2A_2, but otherwise smooth, such that its minimal desingularisation is a K3-surface. In an earlier paper I showd that each such surface is a quotient of a complex torus by a cyclic group of order three. Here I try to classify these K3K3-surfaces, using the period map for complex tori. In particular I show: A K3K3-surface with nine cusps carries polarizations only of degrees 0 or 2 modulo 6. This implies in particular that there is no quartic surface in projective three-space with nine cusps. (T. Urabe pointed out to me how to deduce this from a theorem of Nikulin.) In an appendix I give explicit equations of quartic surfaces in three-space with eight cusps.

Keywords

Cite

@article{arxiv.math/9805082,
  title  = {On the Classification of K3-Surfaces with Nine Cusps},
  author = {W. Barth},
  journal= {arXiv preprint arXiv:math/9805082},
  year   = {2007}
}
R2 v1 2026-07-22T17:58:36.054Z