proposition: Lemma lt_tail0: forall c, nf c -> c <> zero -> gtail c t2< c.
proof: Proof. induction c. - now destruct 2. - cbn; generalize IHc3; case c3; auto with T2. + intros; apply psi_lt_head; inversion_clear H; 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)