English

K3 surfaces with $\mathbb{Z}_2^2$ symplectic action

Algebraic Geometry 2018-07-31 v2

Abstract

Let GG be a finite abelian group which acts symplectically on a K3 surface. The N\'eron-Severi lattice of the projective K3 surfaces admitting GG symplectic action and with minimal Picard number is computed by Garbagnati and Sarti. We consider a 44-dimensional family of projective K3 surfaces with Z22\mathbb{Z}_2^2 symplectic action which do not fall in the above cases. If XX is one of these K3 surfaces, then it arises as the minimal resolution of a specific Z23\mathbb{Z}_2^3-cover of P2\mathbb{P}^2 branched along six general lines. We show that the N\'eron-Severi lattice of XX with minimal Picard number is generated by 2424 smooth rational curves, and that XX specializes to the Kummer surface Km(Ei×Ei)\textrm{Km}(E_i\times E_i). We relate XX to the K3 surfaces given by the minimal resolution of the Z2\mathbb{Z}_2-cover of P2\mathbb{P}^2 branched along six general lines, and the corresponding Hirzebruch-Kummer covering of exponent 22 of P2\mathbb{P}^2.

Keywords

Cite

@article{arxiv.1707.09732,
  title  = {K3 surfaces with $\mathbb{Z}_2^2$ symplectic action},
  author = {Luca Schaffler},
  journal= {arXiv preprint arXiv:1707.09732},
  year   = {2018}
}

Comments

24 pages, 6 figures. Final version with minor corrections and additions. To appear in the Rocky Mountain Journal of Mathematics

R2 v1 2026-06-22T21:01:58.985Z