English

Lifting low-gonal curves for use in Tuitman's algorithm

Number Theory 2020-09-07 v3

Abstract

Consider a smooth projective curve C\overline{C} over a finite field Fq\mathbb{F}_q, equipped with a simply branched morphism CP1\overline{C} \to \mathbb{P}^1 of degree d5d \leq 5. Assume charFq>2\, \mathbb{F}_q > 2 if d4d \leq 4, and charFq>3\, \mathbb{F}_q > 3 if d=5d=5. In this paper we describe how to efficiently compute a lift of C\overline{C} to characteristic zero, such that it can be fed as input to Tuitman's algorithm for computing the Hasse-Weil zeta function of C/Fq\overline{C} / \mathbb{F}_q. Our method relies on the parametrizations of low rank rings due to Delone-Faddeev and Bhargava.

Keywords

Cite

@article{arxiv.2002.10000,
  title  = {Lifting low-gonal curves for use in Tuitman's algorithm},
  author = {Wouter Castryck and Floris Vermeulen},
  journal= {arXiv preprint arXiv:2002.10000},
  year   = {2020}
}

Comments

18 pages

R2 v1 2026-06-23T13:51:01.409Z