fact: Definition on_vert_edge (p : Plane R) (v : vert_edge) : bool := (p.1 == ve_x v) && (ve_bot v < p.2 < ve_top v).
imports: mathcomp(all_ssreflect all_algebra all_real_closed reals) mathcomp.algebra_tactics(ring lra) casteljau convex counterclockwise intersection