(**************************************************************************)
include "basic_2/notation/relations/btsnalt_5.ma".
-include "basic_2/computation/fpbg.ma".
+include "basic_2/computation/fpbg_fpbg.ma".
include "basic_2/computation/fsb.ma".
-(* GENERAL "BIG TREE" STRONGLY NORMALIZING TERMS ****************************)
+(* "QRST" STRONGLY NORMALIZING TERMS ****************************************)
(* Note: alternative definition of fsb *)
inductive fsba (h) (g): relation3 genv lenv term ≝
| fsba_intro: ∀G1,L1,T1. (
- ∀G2,L2,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄ → fsba h g G2 L2 T2
+ ∀G2,L2,T2. ⦃G1, L1, T1⦄ >≡[h, g] ⦃G2, L2, T2⦄ → fsba h g G2 L2 T2
) → fsba h g G1 L1 T1.
interpretation
(* Basic eliminators ********************************************************)
-theorem fsba_ind_alt: ∀h,g. ∀R: relation3 …. (
- ∀G1,L1,T1. ⦃G1, L1⦄ ⊢ ⦥⦥[h,g] T1 → (
- ∀G2,L2,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄ → R G2 L2 T2
- ) → R G1 L1 T1
- ) →
- ∀G,L,T. ⦃G, L⦄ ⊢ ⦥⦥[h, g] T → R G L T.
+lemma fsba_ind_alt: ∀h,g. ∀R: relation3 …. (
+ ∀G1,L1,T1. ⦃G1, L1⦄ ⊢ ⦥⦥[h,g] T1 → (
+ ∀G2,L2,T2. ⦃G1, L1, T1⦄ >≡[h, g] ⦃G2, L2, T2⦄ → R G2 L2 T2
+ ) → R G1 L1 T1
+ ) →
+ ∀G,L,T. ⦃G, L⦄ ⊢ ⦥⦥[h, g] T → R G L T.
#h #g #R #IH #G #L #T #H elim H -G -L -T
/4 width=1 by fsba_intro/
qed-.
+(* Basic properties *********************************************************)
+
+lemma fsba_fpbs_trans: ∀h,g,G1,L1,T1. ⦃G1, L1⦄ ⊢ ⦥⦥[h, g] T1 →
+ ∀G2,L2,T2. ⦃G1, L1, T1⦄ ≥[h, g] ⦃G2, L2, T2⦄ → ⦃G2, L2⦄ ⊢ ⦥⦥[h, g] T2.
+#h #g #G1 #L1 #T1 #H @(fsba_ind_alt … H) -G1 -L1 -T1
+/4 width=5 by fsba_intro, fpbs_fpbg_trans/
+qed-.
+
+(* Main properties **********************************************************)
+
+theorem fsb_fsba: ∀h,g,G,L,T. ⦃G, L⦄ ⊢ ⦥[h, g] T → ⦃G, L⦄ ⊢ ⦥⦥[h, g] T.
+#h #g #G #L #T #H @(fsb_ind_alt … H) -G -L -T
+#G1 #L1 #T1 #_ #IH @fsba_intro
+#G2 #L2 #T2 #H elim (fpbg_inv_fpbu_sn … H) -H
+/3 width=5 by fsba_fpbs_trans/
+qed.
+
(* Main inversion lemmas ****************************************************)
theorem fsba_inv_fsb: ∀h,g,G,L,T. ⦃G, L⦄ ⊢ ⦥⦥[h, g] T → ⦃G, L⦄ ⊢ ⦥[h, g] T.
#h #g #G #L #T #H @(fsba_ind_alt … H) -G -L -T
-/4 width=1 by fsb_intro, fpbc_fpbg/
+/5 width=1 by fsb_intro, fpbc_fpbg, fpbu_fpbc/
+qed-.
+
+(* Advanced properties ******************************************************)
+
+lemma fsb_fpbs_trans: ∀h,g,G1,L1,T1. ⦃G1, L1⦄ ⊢ ⦥[h, g] T1 →
+ ∀G2,L2,T2. ⦃G1, L1, T1⦄ ≥[h, g] ⦃G2, L2, T2⦄ → ⦃G2, L2⦄ ⊢ ⦥[h, g] T2.
+/4 width=5 by fsba_inv_fsb, fsb_fsba, fsba_fpbs_trans/ qed-.
+
+(* Advanced eliminators *****************************************************)
+
+lemma fsb_ind_fpbg: ∀h,g. ∀R:relation3 genv lenv term.
+ (∀G1,L1,T1. ⦃G1, L1⦄ ⊢ ⦥[h, g] T1 →
+ (∀G2,L2,T2. ⦃G1, L1, T1⦄ >≡[h, g] ⦃G2, L2, T2⦄ → R G2 L2 T2) →
+ R G1 L1 T1
+ ) →
+ ∀G1,L1,T1. ⦃G1, L1⦄ ⊢ ⦥[h, g] T1 → R G1 L1 T1.
+#h #g #R #IH #G1 #L1 #T1 #H @(fsba_ind_alt h g … G1 L1 T1)
+/3 width=1 by fsba_inv_fsb, fsb_fsba/
qed-.