- lambdadelta: tentative definition of lazy equivalence for closures +

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / computation / fpbg_fpbg.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma
index 047aee3d4f9d8feb6aaae9721ff26ca012128df4..9022732dcacab28783c945872b5b2a4605ee434d 100644 (file)
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma
@@ -13,7 +13,6 @@
 (**************************************************************************)
 
 include "basic_2/computation/fpbs_alt.ma".
-include "basic_2/computation/fpbs_fpbs.ma".
 include "basic_2/computation/fpbg.ma".
 
 (* GENERAL "BIG TREE" PROPER PARALLEL COMPUTATION FOR CLOSURES **************)
@@ -26,6 +25,21 @@ lemma fpbg_fwd_fpbs: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L
 /3 width=5 by cpxs_fqup_fpbs, fpbs_trans, lpxs_fpbs, cpxs_fpbs/
 qed-.
 
+lemma fpbg_fwd_fpb_sn: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄ →
+                       ∃∃G,L,T. ⦃G1, L1, T1⦄ ≻[h, g] ⦃G, L, T⦄ & ⦃G, L, T⦄ ≥[h, g] ⦃G2, L2, T2⦄.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H elim H -G2 -L2 -T2
+[ #L2 #T2 #HT12 #H #HL12
+  elim (cpxs_neq_inv_step_sn … HT12 H) -HT12 -H
+  /4 width=9 by fpbsa_inv_fpbs, fpbc_cpx, ex3_2_intro, ex2_3_intro/
+| #G2 #L #L2 #T #T2 #HT1 #HT2 #HL2 elim (eq_term_dec T1 T) #H destruct
+  [ -HT1 elim (fqup_inv_step_sn … HT2) -HT2
+    /4 width=9 by fpbsa_inv_fpbs, fpbc_fqu, ex3_2_intro, ex2_3_intro/
+  | elim (cpxs_neq_inv_step_sn … HT1 H) -HT1 -H
+    /5 width=9 by fpbsa_inv_fpbs, fpbc_cpx, fqup_fqus, ex3_2_intro, ex2_3_intro/
+  ]
+]
+qed-.
+
 (* Advanced properties ******************************************************)
 
 lemma fqu_fpbs_fpbg: ∀h,g,G1,G,G2,L1,L,L2,T1,T,T2. ⦃G1, L1, T1⦄ ⊃ ⦃G, L, T⦄ →