X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fcomputation%2Ffsb.ma;h=1616402dec981972dba696ee60e6fe0405a57dc0;hb=e76eade57c0454a58b0d58e5484efe9af417847e;hp=0ad3212fc9a796610ad45e9bbea49b379d3b13fe;hpb=f418a6f9fe878f17a2c7afa0d13a361cce140694;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fsb.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fsb.ma
index 0ad3212fc..1616402de 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/fsb.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fsb.ma
@@ -13,13 +13,14 @@
 (**************************************************************************)
 
 include "basic_2/notation/relations/btsn_5.ma".
-include "basic_2/reduction/fpbc.ma".
+include "basic_2/computation/fpbu.ma".
+include "basic_2/computation/csx_alt.ma".
 
 (* "BIG TREE" STRONGLY NORMALIZING TERMS ************************************)
 
 inductive fsb (h) (g): relation3 genv lenv term ≝
 | fsb_intro: ∀G1,L1,T1. (
-                ∀G2,L2,T2.  ⦃G1, L1, T1⦄ ≻[h, g] ⦃G2, L2, T2⦄ → fsb h g G2 L2 T2
+                ∀G2,L2,T2. ⦃G1, L1, T1⦄ ≻[h, g] ⦃G2, L2, T2⦄ → fsb h g G2 L2 T2
              ) → fsb h g G1 L1 T1
 .
 
@@ -29,15 +30,18 @@ interpretation
 
 (* Basic eliminators ********************************************************)
 
-theorem fsb_ind_alt: ∀h,g. ∀R: relation3 …. (
-                        ∀G1,L1,T1. (
-                           ∀G2,L2,T2. ⦃G1, L1, T1⦄≽ [h, g] ⦃G2, L2, T2⦄ →
-                           (|G1| = |G2| → |L1| = |L2| → T1 = T2 → ⊥) → ⦃G2, L2⦄ ⊢ ⦥[h,g] T2
-                        ) → (
-                           ∀G2,L2,T2. ⦃G1, L1, T1⦄≽ [h, g] ⦃G2, L2, T2⦄ →
-                           (|G1| = |G2| → |L1| = |L2| → T1 = 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 /5 width=1 by fpb_fpbc/
+lemma fsb_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 fsb_intro/
+qed-.
+
+(* Basic inversion lemmas ***************************************************)
+
+lemma fsb_inv_csx: ∀h,g,G,L,T. ⦃G, L⦄ ⊢ ⦥[h, g] T → ⦃G, L⦄ ⊢ ⬊*[h, g] T.
+#h #g #G #L #T #H elim H -G -L -T /5 width=1 by csx_intro_cprs, fpbu_cpxs/
 qed-.