SageMath code to do quadratic Chabauty over imaginary quadratic fields for elliptic curves defined over Q. The rank should be 1 over Q and 2 over the quadratic field.
This is combined with a "sieve" to compute the Q(sqrt(-3))-integral points of y^2 = x^3 - 4 (Folder "Example"). Technically speaking, some spurious points survive the sieve, but they can be ruled out by further arguments.
May 2020
(Francesca Bianchi)