proposition: Lemma LE_zero : forall alpha, nf alpha -> zero t1<= alpha.
proof: Proof. split; auto 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)