-
-lemma leq_inv_sort1_aux: ∀L1,L2,d,e. L1 [d, e] ≈ L2 → L1 = ⋆ → L2 = ⋆.
-#L1 #L2 #d #e #H elim H -H L1 L2 d e
-[ //
-| #L1 #L2 #I1 #I2 #V1 #V2 #_ #_ #H destruct
-| #L1 #L2 #I #V #e #_ #_ #H destruct
-| #L1 #L2 #I1 #I2 #V1 #V2 #d #e #_ #_ #H destruct
-qed.
-
-lemma leq_inv_sort1: ∀L2,d,e. ⋆ [d, e] ≈ L2 → L2 = ⋆.
-/2 width=5/ qed.
-
-lemma leq_inv_sort2: ∀L1,d,e. L1 [d, e] ≈ ⋆ → L1 = ⋆.
-/3/ qed.