English

Good elliptic curves with a specified torsion subgroup

Number Theory 2022-08-30 v2

Abstract

An elliptic curve EE over Q\mathbb{Q} is said to be good if NE6<max ⁣{c43,c62}N_{E}^{6}<\max\!\left\{ \left\vert c_{4}^{3}\right\vert ,c_{6}^{2}\right\} where NEN_{E} is the conductor of EE and c4c_{4} and c6c_{6} are the invariants associated to a global minimal model of EE. In this article, we generalize Masser's Theorem on the existence of infinitely many good elliptic curves with full 22-torsion. Specifically, we prove via constructive methods that for each of the fifteen torsion subgroups TT allowed by Mazur's Torsion Theorem, there are infinitely many good elliptic curves EE with E ⁣(Q)torsTE\!\left(\mathbb{Q}\right) _{\text{tors}}\cong T.

Keywords

Cite

@article{arxiv.2012.12475,
  title  = {Good elliptic curves with a specified torsion subgroup},
  author = {Alexander J. Barrios},
  journal= {arXiv preprint arXiv:2012.12475},
  year   = {2022}
}

Comments

19 pages; incorporates referee's suggestions; final version to appear in Journal of Number Theory

R2 v1 2026-06-23T21:15:46.715Z