+lemma cnv_inv_lref_pair (h) (a) (G):
+ ∀i,L. ❪G,L❫ ⊢ #i ![h,a] →
+ ∀I,K,V. ⇩[i] L ≘ K.ⓑ[I]V → ❪G,K❫ ⊢ V ![h,a].
+#h #a #G #i #L #H #I #K #V #HLK
+elim (cnv_inv_lref_drops … H) -H #Z #Y #X #HLY #HX
+lapply (drops_mono … HLY … HLK) -L #H destruct //
+qed-.
+
+lemma cnv_inv_lref_atom (h) (a) (b) (G):
+ ∀i,L. ❪G,L❫ ⊢ #i ![h,a] → ⇩*[b,𝐔❨i❩] L ≘ ⋆ → ⊥.
+#h #a #b #G #i #L #H #Hi
+elim (cnv_inv_lref_drops … H) -H #Z #Y #X #HLY #_
+lapply (drops_gen b … HLY) -HLY #HLY
+lapply (drops_mono … HLY … Hi) -L #H destruct
+qed-.
+
+lemma cnv_inv_lref_unit (h) (a) (G):
+ ∀i,L. ❪G,L❫ ⊢ #i ![h,a] →
+ ∀I,K. ⇩[i] L ≘ K.ⓤ[I] → ⊥.
+#h #a #G #i #L #H #I #K #HLK
+elim (cnv_inv_lref_drops … H) -H #Z #Y #X #HLY #_
+lapply (drops_mono … HLY … HLK) -L #H destruct
+qed-.
+