Descent via isogeny in dimension 2

A technique of descent via 4-isogeny is developed on the Jacobian of a curve of genus 2 of the form: $Y^2 = q_1(X)q_2(X)q_3(X)$, where each $q_i(X)$ is a quadratic defined over Q. The technique offers a realistic prospect of calculating rank tables of Mordell-Weil groups in higher dimension. A selec...