proposition: Fact anti : antisymmetric le.
proof: Proof. by elim=> [|x s ihs] [|y s'] //=; rewrite andbACA => /andP[/le_anti-> /ihs->]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)