proposition: Lemma lt_rank : {mono rank : p q / p < q}.
proof: Proof. by move=> p q; rewrite !ltNge le_rank. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)