Heegner point


In mathematics, a Heegner point is a point on a modular curve that is the image of a quadratic imaginary point of the upper half-plane. They were defined by Bryan Birch and named after Kurt Heegner, who used similar ideas to prove Gauss's conjecture on imaginary quadratic fields of class number one.

Gross–Zagier theorem

The Gross–Zagier theorem describes the height of Heegner points in terms of a derivative of the L-function of the elliptic curve at the point s = 1. In particular if the elliptic curve has rank 1, then the Heegner points can be used to construct a rational point on the curve of infinite order. More generally, showed that Heegner points could be used to construct rational points on the curve for each positive integer n, and the heights of these points were the coefficients of a modular form of weight 3/2. Shou-Wu Zhang generalized the Gross–Zagier theorem from elliptic curves to the case of modular abelian varieties.

Birch and Swinnerton-Dyer conjecture

later used Heegner points to construct Euler systems, and used this to prove much of the Birch-Swinnerton-Dyer conjecture for rank 1 elliptic curves. Brown proved the Birch–Swinnerton-Dyer conjecture for most rank 1 elliptic curves over global fields of positive characteristic.

Computation

Heegner points can be used to compute very large rational points on rank 1 elliptic curves that could not be found by naive methods. Implementation of the algorithm is available in Magma, PARI/GP, and Sage.