-(*
-fact ltps_inv_atom2_aux: ∀d,e,L1,L2.
- L1 [d, e] ≫ L2 → L2 = ⋆ → L1 = ⋆.
-#d #e #L1 #L2 * -d e L1 L2
-[ //
-| #L #I #V #H destruct
-| #L1 #L2 #I #V1 #V2 #e #_ #_ #H destruct
-| #L1 #L2 #I #V1 #V2 #d #e #_ #_ #H destruct
-]
+
+fact ltpss_inv_atom2_aux: ∀d,e,L1,L2.
+ L1 [d, e] ≫* L2 → L2 = ⋆ → L1 = ⋆.
+#d #e #L1 #L2 #H @(ltpss_ind … H) -L2 //
+#L2 #L #_ #HL2 #IHL2 #H destruct -L;
+lapply (ltps_inv_atom2 … HL2) -HL2 /2/