In the approach, the on-shell scattering process "tree" is described by a positive Grassmannian, a structure in algebraic geometry analogous to a convex polytope, that generalizes the idea of a simplex in projective space.
When the volume of the amplituhedron is calculated in the planar limit of N = 4 D = 4 supersymmetric Yang-Mills theory, it describes the scattering amplitudes of subatomic particles.