Twistor Correspondence

Oriented spheres in complex Euclidean three-space can be represented as lines in complex projective three-space ("Lie correspondence"), and the spheres may be thought of as the representation of the light cones of events in Minkowski space. In effect, the Lie correspondence represents the points of (complexified compactified) Minkowski space by lines in complex projective three-space, where meeting lines describe null-separated Minkowski points. This is the twistor correspondence.