proposition: Lemma nodup_nids: NoDup nids.
proof: Proof. intros. unfold nids. destruct (bnats MaxNId) as [nids B N]. assumption. Qed.
imports: Coq(FunctionalExtensionality Arith Lia) Coq(Arith.Peano_dec Arith.Compare_dec) Coq(Relations.Relation_Operators) Coq(List) Chapar(Predefs)