proposition: Lemma sorted_mask_sort_le s (m : bitseq) : sorted <=%O (mask m s) -> {m_s : bitseq | mask m_s (sort <=%O s) = mask m s}.
proof: Proof. exact/sorted_mask_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)