-lemma lifts_lift_trans_le: ∀T1,T,des. ⬆*[des] T1 ≡ T → ∀T2. ⬆[0, 1] T ≡ T2 →
- ∃∃T0. ⬆[0, 1] T1 ≡ T0 & ⬆*[des + 1] T0 ≡ T2.
-#T1 #T #des #H elim H -T1 -T -des
-[ /2 width=3/
-| #T1 #T3 #T #des #l #m #HT13 #_ #IHT13 #T2 #HT2
+lemma lifts_lift_trans_le: ∀T1,T,cs. ⬆*[cs] T1 ≡ T → ∀T2. ⬆[0, 1] T ≡ T2 →
+ ∃∃T0. ⬆[0, 1] T1 ≡ T0 & ⬆*[cs + 1] T0 ≡ T2.
+#T1 #T #cs #H elim H -T1 -T -cs
+[ /2 width=3 by lifts_nil, ex2_intro/
+| #T1 #T3 #T #cs #l #m #HT13 #_ #IHT13 #T2 #HT2