proposition: Lemma path_all_llen a l: path llen a l -> all (llen a) l.
proof: Proof. by apply: (order_path_min transitive_llen). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)