proposition: Lemma open_exp_wrt_exp_rec_close_exp_wrt_exp_rec_mutual : (forall e1 x1 n1, open_exp_wrt_exp_rec n1 (var_f x1) (close_exp_wrt_exp_rec n1 x1 e1) = e1).
proof: Proof. apply_mutual_ind exp_mutind; default_simp. Qed.
imports: Coq.Logic.FunctionalExtensionality Coq.Program.Equality Metalib.Metatheory Metalib.LibLNgen Stlc