proposition: Lemma degree_exp_wrt_exp_open_exp_wrt_exp_rec_inv_mutual : (forall e1 e2 n1, degree_exp_wrt_exp n1 (open_exp_wrt_exp_rec n1 e2 e1) -> degree_exp_wrt_exp (S n1) e1).
proof: Proof. apply_mutual_ind exp_mutind; default_simp; eauto with lngen. Qed.
imports: Coq.Logic.FunctionalExtensionality Coq.Program.Equality Metalib.Metatheory Metalib.LibLNgen Stlc