-lemma cnr_inv_abst: ∀a,L,V,T. ⦃G, L⦄ ⊢ 𝐍⦃ⓛ{a}V.T⦄ → ⦃G, L⦄ ⊢ 𝐍⦃V⦄ ∧ L.ⓛV ⊢ 𝐍⦃T⦄.
-#a #L #V1 #T1 #HVT1 @conj
-[ #V2 #HV2 lapply (HVT1 (ⓛ{a}V2.T1) ?) -HVT1 /2 width=2/ -HV2 #H destruct //
-| #T2 #HT2 lapply (HVT1 (ⓛ{a}V1.T2) ?) -HVT1 /2 width=2/ -HT2 #H destruct //
+lemma cnr_inv_abst: ∀a,G,L,V,T. ⦃G, L⦄ ⊢ 𝐍⦃ⓛ{a}V.T⦄ → ⦃G, L⦄ ⊢ 𝐍⦃V⦄ ∧ ⦃G, L.ⓛV⦄ ⊢ 𝐍⦃T⦄.
+#a #G #L #V1 #T1 #HVT1 @conj
+[ #V2 #HV2 lapply (HVT1 (ⓛ{a}V2.T1) ?) -HVT1 /2 width=2 by cpr_pair_sn/ -HV2 #H destruct //
+| #T2 #HT2 lapply (HVT1 (ⓛ{a}V1.T2) ?) -HVT1 /2 width=2 by cpr_bind/ -HT2 #H destruct //