+qed-.
+
+lemma cnv_inv_lref_atom (a) (h) (b) (G):
+ ∀i,L. ⦃G, L⦄ ⊢ #i ![a, h] →
+ ⬇*[b,𝐔❴i❵] L ≘ ⋆ → ⊥.
+#a #h #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 (a) (h) (G):
+ ∀i,L. ⦃G, L⦄ ⊢ #i ![a, h] →
+ ∀I,K. ⬇*[i] L ≘ K.ⓤ{I} → ⊥.
+#a #h #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-.