English

The arithmetic of tame quotient singularities in dimension $2$

Algebraic Geometry 2023-11-29 v3 Number Theory

Abstract

Let kk be a field, XX a variety with tame quotient singularities and X~X\tilde{X}\to X a resolution of singularities. Any smooth rational point xX(k)x\in X(k) lifts to X~\tilde{X} by the Lang-Nishimura theorem, but if xx is singular this might be false. For certain types of singularities the rational point is guaranteed to lift, though; these are called singularities of type R\mathrm{R}. This concept has applications in the study of the fields of moduli of varieties and yields an enhanced version of the Lang-Nishimura theorem where the smoothness assumption is relaxed. We classify completely the tame quotient singularities of type R\mathrm{R} in dimension 22; in particular, we show that every non-cyclic tame quotient singularity in dimension 22 is of type R\mathrm{R}, and most cyclic singularities are of type R\mathrm{R} too.

Keywords

Cite

@article{arxiv.2211.05669,
  title  = {The arithmetic of tame quotient singularities in dimension $2$},
  author = {Giulio Bresciani},
  journal= {arXiv preprint arXiv:2211.05669},
  year   = {2023}
}