Currently displaying 1 – 3 of 3

Showing per page

Order by Relevance | Title | Year of publication

On families of 9-congruent elliptic curves

Tom Fisher — 2015

Acta Arithmetica

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.

Some examples of 5 and 7 descent for elliptic curves over Q

Tom Fisher — 2001

Journal of the European Mathematical Society

We perform descent calculations for the families of elliptic curves over Q with a rational point of order n = 5 or 7. These calculations give an estimate for the Mordell-Weil rank which we relate to the parity conjecture. We exhibit explicit elements of the Tate-Shafarevich group of order 5 and 7, and show that the 5-torsion of the Tate-Shafarevich group of an elliptic curve over Q may become arbitrarily large.

Ranks of quadratic twists of elliptic curves

Mark WatkinsStephen DonnellyNoam D. ElkiesTom FisherAndrew GranvilleNicholas F. Rogers — 2014

Publications mathématiques de Besançon

We report on a large-scale project to investigate the ranks of elliptic curves in a quadratic twist family, focussing on the congruent number curve. Our methods to exclude candidate curves include 2-Selmer, 4-Selmer, and 8-Selmer tests, the use of the Guinand-Weil explicit formula, and even 3-descent in a couple of cases. We find that rank 6 quadratic twists are reasonably common (though still quite difficult to find), while rank 7 twists seem much more rare. We also describe our inability to find...

Page 1

Download Results (CSV)