English

Enriques involutions and Brauer classes

Algebraic Geometry 2022-02-17 v1

Abstract

We prove that every element of order 2 in the Brauer group of a complex Kummer surface X descends to an Enriques quotient of X. In 'generic' cases this gives a bijection between the set Enr(X) of Enriques quotients of X up to isomorphism and the set of Brauer classes of X of order 2. For some K3 surfaces of Picard rank 20 we prove that the fibres of the map from Enr(X) to Br(X)[2] above the non-zero points have the same order.

Keywords

Cite

@article{arxiv.2202.08030,
  title  = {Enriques involutions and Brauer classes},
  author = {Alexei N. Skorobogatov and Domenico Valloni},
  journal= {arXiv preprint arXiv:2202.08030},
  year   = {2022}
}

Comments

18 pages

R2 v1 2026-06-24T09:40:48.978Z