(* *)
(**************************************************************************)
-include "basic_2/notation/relations/predsn_8.ma".
-include "basic_2/grammar/bteq.ma".
+include "basic_2/notation/relations/btpredsn_8.ma".
+include "basic_2/relocation/lleq.ma".
include "basic_2/reduction/lpx.ma".
-(* ADJACENT "BIG TREE" NORMAL FORMS *****************************************)
+(* REDUCTION FOR "BIG TREE" NORMAL FORMS ************************************)
-definition fpn: ∀h. sd h → tri_relation genv lenv term ≝
- λh,g,G1,L1,T1,G2,L2,T2.
- ∧∧ G1 = G2 & ⦃G1, L1⦄ ⊢ ➡[h, g] L2 & T1 = T2.
+inductive fpn (h) (g) (G) (L1) (T): relation3 genv lenv term ≝
+| fpn_intro: ∀L2. ⦃G, L1⦄ ⊢ ➡[h, g] L2 → L1 ⋕[T] L2 → fpn h g G L1 T G L2 T
+.
interpretation
- "adjacent 'big tree' normal forms (closure)"
- 'PRedSn h g G1 L1 T1 G2 L2 T2 = (fpn h g G1 L1 T1 G2 L2 T2).
+ "reduction for 'big tree' normal forms (closure)"
+ 'BTPRedSn h g G1 L1 T1 G2 L2 T2 = (fpn h g G1 L1 T1 G2 L2 T2).
(* Basic_properties *********************************************************)
lemma fpn_refl: ∀h,g. tri_reflexive … (fpn h g).
-/2 width=1 by and3_intro/ qed.
+/2 width=1 by fpn_intro/ qed.
-(* Basic forward lemmas *****************************************************)
+(* Basic inversion lemmas ***************************************************)
-lemma fpn_fwd_bteq: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊢➡[h, g] ⦃G2, L2, T2⦄ →
- ⦃G1, L1, T1⦄ ⋕ ⦃G2, L2, T2⦄.
-#h #g #G1 #G2 #L1 #L2 #T1 #T2 * /3 width=4 by lpx_fwd_length, and3_intro/
+lemma fpn_inv_gen: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊢ ⋕➡[h, g] ⦃G2, L2, T2⦄ →
+ ∧∧ G1 = G2 & ⦃G1, L1⦄ ⊢ ➡[h, g] L2 & L1 ⋕[T1] L2 & T1 = T2.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 * -G2 -L2 -T2 /2 width=1 by and4_intro/
qed-.