proposition: Fact anti : antisymmetric le.
proof: Proof. by move=> x y /le_anti /(pcan_inj f_can). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)