proposition: Theorem le_tail : forall a n b b', leq lt b b' -> leq lt (cons a n b) (cons a n b').
proof: Proof. intros * H; rewrite le_lt_eq in *; destruct H. - auto with T1. - subst b; 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)