Torsion points of small order on cyclic covers of $\mathbb{P}^1$. III
Abstract
Let be an integer and a perfect field such that does not divide . Let be an integer that is prime to . Let be a degree monic polynomial without repeated roots, and a smooth projective model of the affine curve . Let be the Jacobian of the -curve . As usual, we identify with its canonical image in (such that the only ``infinite point'' of goes to the zero of the group law on ). We say that an integer is -reachable over if there exists a polynomial as above such that contains a torsion point of order . Let us put . Earlier we proved that if is -reachable, then either or or (in addition, both and are -reachable over every ). We also proved that if is -reachable over some then . In the present paper we discuss the -reachability of when or .
Cite
@article{arxiv.2601.12643,
title = {Torsion points of small order on cyclic covers of $\mathbb{P}^1$. III},
author = {Boris M. Bekker and Yuri G. Zarhin},
journal= {arXiv preprint arXiv:2601.12643},
year = {2026}
}
Comments
24 pages