proposition: Lemma is_finite_finite : forall alpha, is_finite alpha -> {n : nat | alpha = fin n}.
proof: Proof. destruct 1. - exists 0;cbn;auto with T2. - exists (S n);cbn;auto with T2. Qed.
imports: Coq(Arith List Lia Compare_dec Relations Wellfounded RelationClasses) hydras(Epsilon0) hydras(More_Arith Restriction) hydras(ON_Generic) hydras(rpo.term rpo.rpo) hydras(T2) hydras(Compat815)