proposition: Lemma close_exp_wrt_exp_rec_inj_mutual : (forall e1 e2 x1 n1, close_exp_wrt_exp_rec n1 x1 e1 = close_exp_wrt_exp_rec n1 x1 e2 -> e1 = e2).
proof: Proof. apply_mutual_ind exp_mutind; intros; match goal with | |- _ = ?term => destruct term end; default_simp; eauto with lngen. Qed.
imports: Coq.Logic.FunctionalExtensionality Coq.Program.Equality Metalib.Metatheory Metalib.LibLNgen Stlc