English

Abelian surfaces over finite fields containing no curves of genus $3$ or less

Algebraic Geometry 2026-03-12 v4 Number Theory

Abstract

We study abelian surfaces defined over finite fields which do not contain any possibly singular curve of genus less than or equal to 33. Firstly, we complete and expand the characterisation of isogeny classes of abelian surfaces with no curves of genus up to 22 initiated by the first author \emph{et al.~}in previous work. Secondly, we show that, for simple abelian surfaces, containing a curve of genus 33 is equivalent to admitting a polarisation of degree 44. Thanks to this result, we can use existing algorithms to check which isomorphism classes in the isogeny classes containing no genus 22 curves have a polarisation of degree 44. Thirdly, we characterise isogeny classes of abelian surfaces with no curves of genus 2\leq 2, containing no abelian surface with a polarisation of degree 44. Finally, we describe the absolutely irreducible genus 33 curves lying on abelian surfaces containing no curves of genus less than or equal to 22.

Keywords

Cite

@article{arxiv.2408.02493,
  title  = {Abelian surfaces over finite fields containing no curves of genus $3$ or less},
  author = {Elena Berardini and Alejandro Giangreco Maidana and Stefano Marseglia},
  journal= {arXiv preprint arXiv:2408.02493},
  year   = {2026}
}

Comments

Accepted for publication in Journal of Pure and Applied Algebra