fact: Definition bet' a b c := bet (a 0 0)%:M (b 0 0)%:M (c 0 0)%:M && bet (a 0 1)%:M (b 0 1)%:M (c 0 1)%:M.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrfun ssrnat eqtype choice seq) mathcomp(fintype finset finfun bigop order) mathcomp(ssralg ssrnum path generic_quotient matrix mxalgebra) mathcomp(zmodp) GeoCoq.Meta_theory.Models.POF_to_Tarski GeoCoq.Meta_theory.Counter_models.Planar.independence