An incidence relation for the Klein correspondence carries alpha planes in the complexified, compactified form of this structure to projective twistors.
A certain extension of this structure is a big cell of the Grassmannian G(2,4) ["G-2-comma-4"]. Adding the "U equals W" generator of the null cone of the origin in R6 ["R-6"] makes this structure conformally symmetric. A technique for solving problems in this structure transforms the Schroedinger equation into the heat equation. An incidence relation for the Klein correspondence carries alpha planes in the complexified, compactified form of this structure to projective twistors. Dynamic equations in this structure can be rewritten as static equations in a related structure using the Wick rotation. This structure's classical form is pseudo-Riemannian and has metric signature (-,+,+,+) ["minus plus plus plus"]. The Poincaré group contains this structure's isometries, which include translations, rotations, and boosts. In this structure, light rays travel along null vectors, and intervals separate events. For 10 points, name this four-dimensional manifold that is the natural setting for special relativity.
A certain extension of this structure is a big cell of the Grassmannian G(2,4)
Minkowski spacetime [prompt on "(flat) spacetime"]