proposition: Lemma sort_lt_sorted s : sorted <%O (sort <=%O s) = uniq s.
proof: Proof. by rewrite lt_sorted_uniq_le sort_uniq sort_le_sorted andbT. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)