English

On families of 9-congruent elliptic curves

Number Theory 2015-04-30 v1

Abstract

We compute equations for the families of elliptic curves 9-congruent to a given elliptic curve. We use these to find infinitely many non-trivial pairs of 9-congruent elliptic curves over Q, i.e. pairs of non-isogenous elliptic curves over Q whose 9-torsion subgroups are isomorphic as Galois modules.

Keywords

Cite

@article{arxiv.1504.07891,
  title  = {On families of 9-congruent elliptic curves},
  author = {Tom Fisher},
  journal= {arXiv preprint arXiv:1504.07891},
  year   = {2015}
}

Comments

18 pages. This article supersedes parts of arXiv:1105.1706