-lemma tdeq_inv_lifts_sn: ∀h,o. deliftable2_sn (tdeq h o).
-#h #o #U1 #U2 #H elim H -U1 -U2 [||| * ]
-[ #s1 #s2 #d #Hs1 #Hs2 #f #X #H >(lifts_inv_sort2 … H) -H
- /3 width=5 by lifts_sort, tdeq_sort, ex2_intro/
+lemma tdeq_inv_lifts_sn: deliftable2_sn tdeq.
+#U1 #U2 #H elim H -U1 -U2 [||| * ]
+[ #s1 #s2 #f #X #H >(lifts_inv_sort2 … H) -H
+ /3 width=3 by lifts_sort, tdeq_sort, ex2_intro/