proposition: Lemma nfb_a a b n c: nfb (gcons a b n c) -> nfb a.
proof: Proof. cbn. destruct c. destruct (nfb b), ( nfb a);cbn; auto. destruct (compare [c1, c2] [a, b]);try discriminate. destruct (nfb a); cbn; auto. 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)