1 (**************************************************************************)
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 *)
13 (**************************************************************************)
15 include "basic_2/notation/relations/btpred_8.ma".
16 include "basic_2/relocation/fquq.ma".
17 include "basic_2/substitution/lleq.ma".
18 include "basic_2/reduction/lpx.ma".
20 (* "BIG TREE" PARALLEL REDUCTION FOR CLOSURES *******************************)
22 inductive fpb (h) (g) (G1) (L1) (T1): relation3 genv lenv term ≝
23 | fpb_fquq: ∀G2,L2,T2. ⦃G1, L1, T1⦄ ⊐⸮ ⦃G2, L2, T2⦄ → fpb h g G1 L1 T1 G2 L2 T2
24 | fpb_cpx : ∀T2. ⦃G1, L1⦄ ⊢ T1 ➡[h, g] T2 → fpb h g G1 L1 T1 G1 L1 T2
25 | fpb_lpx : ∀L2. ⦃G1, L1⦄ ⊢ ➡[h, g] L2 → fpb h g G1 L1 T1 G1 L2 T1
26 | fpb_lleq: ∀L2. L1 ⋕[T1, 0] L2 → fpb h g G1 L1 T1 G1 L2 T1
30 "'big tree' parallel reduction (closure)"
31 'BTPRed h g G1 L1 T1 G2 L2 T2 = (fpb h g G1 L1 T1 G2 L2 T2).
33 (* Basic properties *********************************************************)
35 lemma fpb_refl: ∀h,g. tri_reflexive … (fpb h g).
36 /2 width=1 by fpb_cpx/ qed.
38 lemma cpr_fpb: ∀h,g,G,L,T1,T2. ⦃G, L⦄ ⊢ T1 ➡ T2 → ⦃G, L, T1⦄ ≽[h, g] ⦃G, L, T2⦄.
39 /3 width=1 by fpb_cpx, cpr_cpx/ qed.
41 lemma lpr_fpb: ∀h,g,G,L1,L2,T. ⦃G, L1⦄ ⊢ ➡ L2 → ⦃G, L1, T⦄ ≽[h, g] ⦃G, L2, T⦄.
42 /3 width=1 by fpb_lpx, lpr_lpx/ qed.