proposition: Lemma lt_path_filter x a s : path <%O x s -> path <%O x (filter a s).
proof: Proof. exact/path_filter/lt_trans. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)