proposition: Lemma degree_exp_wrt_exp_S_mutual : (forall n1 e1, degree_exp_wrt_exp n1 e1 -> degree_exp_wrt_exp (S n1) e1).
proof: Proof. apply_mutual_ind degree_exp_wrt_exp_mutind; default_simp. Qed.
imports: Coq.Logic.FunctionalExtensionality Coq.Program.Equality Metalib.Metatheory Metalib.LibLNgen Stlc