English

Quotients of del Pezzo surfaces of degree 2

Algebraic Geometry 2018-03-21 v3

Abstract

Let k\Bbbk be any field of characteristic zero, XX be a del Pezzo surface of degree~22 and GG be a group acting on XX. In this paper we study k\Bbbk-rationality questions for the quotient surface X/GX / G. If there are no smooth k\Bbbk-points on X/GX / G then X/GX / G is obviously non-k\Bbbk-rational. Assume that the set of smooth k\Bbbk-points on the quotient is not empty. We find a list of groups, such that the quotient surface can be non-k\Bbbk-rational. For these groups we construct examples of both k\Bbbk-rational and non-k\Bbbk-rational quotients of both k\Bbbk-rational and non-k\Bbbk-rational del Pezzo surfaces of degree 22 such that the GG-invariant Picard number of XX is 11. For all other groups we show that the quotient X/GX / G is always k\Bbbk-rational.

Keywords

Cite

@article{arxiv.1709.02006,
  title  = {Quotients of del Pezzo surfaces of degree 2},
  author = {Andrey Trepalin},
  journal= {arXiv preprint arXiv:1709.02006},
  year   = {2018}
}

Comments

2nd version. 39 pages, 5 tables