(* Main properties **********************************************************)
theorem lifts_trans: ∀T1,T,cs1. ⬆*[cs1] T1 ≡ T → ∀T2:term. ∀cs2. ⬆*[cs2] T ≡ T2 →
(* Main properties **********************************************************)
theorem lifts_trans: ∀T1,T,cs1. ⬆*[cs1] T1 ≡ T → ∀T2:term. ∀cs2. ⬆*[cs2] T ≡ T2 →