English

From Picard groups of hyperelliptic curves to class groups of quadratic fields

Number Theory 2020-12-16 v2

Abstract

Let CC be a hyperelliptic curve defined over Q\mathbb{Q}, whose Weierstrass points are defined over extensions of Q\mathbb{Q} of degree at most three, and at least one of them is rational. Generalizing a result of R. Soleng (in the case of elliptic curves), we prove that any line bundle of degree 00 on CC which is not torsion can be specialised into ideal classes of imaginary quadratic fields whose order can be made arbitrarily large. This gives a positive answer, for such curves, to a question by Agboola and Pappas.

Keywords

Cite

@article{arxiv.1807.02823,
  title  = {From Picard groups of hyperelliptic curves to class groups of quadratic fields},
  author = {Jean Gillibert},
  journal= {arXiv preprint arXiv:1807.02823},
  year   = {2020}
}

Comments

28 pages, LaTeX. Minor improvements following the referee's suggestions. New proof of Lemma 3.10. To appear in Trans. Amer. Math. Soc