English

On the existence of curves with a triple point on a K3 surface

Algebraic Geometry 2012-09-05 v4

Abstract

Let (S,H)(S,H) be a general primitively polarized K3K3 surface of genus \p\p and let pa(nH)p_a(nH) be the arithmetic genus of nH.nH. We prove the existence in OS(nH)|\mathcal O_S(nH)| of curves with a triple point and AkA_k-singularities. In particular, we show the existence of curves of geometric genus gg in OS(nH)|\mathcal O_S(nH)| with a triple point and nodes as singularities and corresponding to regular points of their equisingular deformation locus, for every 1gpa(nH)31\leq g\leq p_a(nH)-3 and (\p,n)(4,1).(\p,n)\neq (4,1). Our result is obtained by studying the versal deformation space of a non-planar quadruple point.

Keywords

Cite

@article{arxiv.1111.3051,
  title  = {On the existence of curves with a triple point on a K3 surface},
  author = {Concettina Galati},
  journal= {arXiv preprint arXiv:1111.3051},
  year   = {2012}
}

Comments

18 pages; 2 figures; references updated; typos corrected; minor changes in the abstract and in the statement of Lemma 4.1 and Theorem 1.1; a mistake in the proof of Theorem 1.1 corrected; Remark 4.4 added; statement of Corollary 4.3 corrected; final version incorporating the referees corrections. To appear on Rend. Lincei Math. Appl