English

On families of n-congruent elliptic curves

Number Theory 2011-05-10 v1

Abstract

We use an invariant-theoretic method to compute certain twists of the modular curves X(n) for n=7,9,11. Searching for rational points on these twists enables us to find non-trivial pairs of n-congruent elliptic curves over Q, i.e. pairs of non-isogenous elliptic curves over Q whose n-torsion subgroups are isomorphic as Galois modules. We also show by giving explicit non-trivial examples over Q(T) that there are infinitely many examples over Q in the cases n=9 and n=11.

Keywords

Cite

@article{arxiv.1105.1706,
  title  = {On families of n-congruent elliptic curves},
  author = {Tom Fisher},
  journal= {arXiv preprint arXiv:1105.1706},
  year   = {2011}
}

Comments

57 pages