proposition: Lemma subst_exp_open_exp_wrt_exp_rec_mutual : (forall e3 e1 e2 x1 n1, lc_exp e1 -> subst_exp e1 x1 (open_exp_wrt_exp_rec n1 e2 e3) = open_exp_wrt_exp_rec n1 (subst_exp e1 x1 e2) (subst_exp e1 x1 e3)).
proof: Proof. apply_mutual_ind exp_mutind; default_simp. Qed.
imports: Coq.Logic.FunctionalExtensionality Coq.Program.Equality Metalib.Metatheory Metalib.LibLNgen Stlc