Rational points on elliptic curves over the rationals Using ell2cover The function ell2cover returns a basis of the set of everywhere locally soluble 2-covers of the curve. A cover is given by a pair [Q, M]. The 2-cover is given by the quartic y2 = Q(x) and M is a map from the quartic to the curve. Finding a point on the cover allows to find a point on the curve. ? E=ellinit([1,0,1,-32866776356,-2293423702808798]); ? ellrank(E) %13 = [2,2,0,[[55989637/144,360928708609/1728]]] The rank is 2 but we have only one point. We can try to find the second point manually with ell2cover.