fact: Variables (x y z : T) (cmp_xy : x >=< y) (cmp_xz : x >=< z) (cmp_yz : y >=< z).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)