proposition: Lemma nf_intro : forall a n b, nf a -> nf b -> b <_phi0 a -> nf (cons a n b).
proof: Proof. destruct 3; eauto with T1. Qed.
imports: Coq(Arith Max Bool Lia Compare_dec Relations Ensembles Wellfounded Bool RelationClasses Operators_Properties ArithRing Logic.Eqdep_dec) hydras(More_Arith Restriction DecPreOrder) hydras(OrdNotations)