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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
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15 include "apps_2/models/model_vlift.ma".
16 include "apps_2/models/vdrop.ma".
18 (* EVALUATION DROP **********************************************************)
20 (* Advanced properties with evaluation evaluation lift **********************)
22 lemma vlift_vdrop_eq (M): ∀lv,i. lv ≐{?,dd M} ⫯[i←lv i]⫰[i]lv.
23 #M #lv #i #j elim (lt_or_eq_or_gt j i) #Hji destruct
24 [ >vlift_lt // >vdrop_lt //
26 | >vlift_gt // >vdrop_ge /2 width=1 by monotonic_pred/
27 <(lt_succ_pred … Hji) //