proposition: Lemma GnawS_Gnaw (s:list nat) : forall alpha, Gnaw alpha s = GnawS alpha (unshift s).
proof: Proof. unfold Gnaw, GnawS. intros; apply gnaw_gnawS. Qed.
imports: hydras(E0 Canon Paths) hydras(MoreLists Iterates Exp2) Coq(Lia Compare_dec)