proposition: Lemma subseq_sort_le : {homo sort <=%O : s1 s2 / @subseq T s1 s2}.
proof: Proof. exact/subseq_sort/le_trans/le_total. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)