(* Basic properties *********************************************************)
lemma cpr_intro: ∀L,T1,T,T2,d,e. T1 ➡ T → L ⊢ T ▶* [d, e] T2 → L ⊢ T1 ➡ T2.
-/4 width=3/ qed-.
+/3 width=5/ qed-.
(* Basic_1: was by definition: pr2_free *)
lemma cpr_tpr: ∀T1,T2. T1 ➡ T2 → ∀L. L ⊢ T1 ➡ T2.