X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Frt_computation%2Flfsx_lfsx.ma;h=acb4447e3ea90fe82511b2258e9945569d5c3197;hb=47a745462a714af9d65cea7b61af56524bd98fa1;hp=7e1d5cffb36d200d89b1416f2f24a78d0be4d510;hpb=670ad7822d59e598a38d9037d482d3de188b170c;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/rt_computation/lfsx_lfsx.ma b/matita/matita/contribs/lambdadelta/basic_2/rt_computation/lfsx_lfsx.ma
index 7e1d5cffb..acb4447e3 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/rt_computation/lfsx_lfsx.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/rt_computation/lfsx_lfsx.ma
@@ -12,7 +12,6 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include "basic_2/static/lfdeq_lfdeq.ma".
 include "basic_2/rt_transition/lfpx_lfdeq.ma".
 include "basic_2/rt_computation/lfsx.ma".
 
@@ -20,16 +19,16 @@ include "basic_2/rt_computation/lfsx.ma".
 
 (* Advanced properties ******************************************************)
 
-(* Basic_2A1: was just: lsx_lleq_trans *)
+(* Basic_2A1: uses: lsx_lleq_trans *)
 lemma lfsx_lfdeq_trans: ∀h,o,G,L1,T. G ⊢ ⬈*[h, o, T] 𝐒⦃L1⦄ →
-                        ∀L2. L1 ≡[h, o, T] L2 → G ⊢ ⬈*[h, o, T] 𝐒⦃L2⦄.
+                        ∀L2. L1 ≛[h, o, T] L2 → G ⊢ ⬈*[h, o, T] 𝐒⦃L2⦄.
 #h #o #G #L1 #T #H @(lfsx_ind … H) -L1
 #L1 #_ #IHL1 #L2 #HL12 @lfsx_intro
 #L #HL2 #HnL2 elim (lfdeq_lfpx_trans … HL2 … HL12) -HL2
 /4 width=5 by lfdeq_repl/
 qed-.
 
-(* Basic_2A1: was: lsx_lpx_trans *)
+(* Basic_2A1: uses: lsx_lpx_trans *)
 lemma lfsx_lfpx_trans: ∀h,o,G,L1,T. G ⊢ ⬈*[h, o, T] 𝐒⦃L1⦄ →
                        ∀L2. ⦃G, L1⦄ ⊢ ⬈[h, T] L2 → G ⊢ ⬈*[h, o, T] 𝐒⦃L2⦄.
 #h #o #G #L1 #T #H @(lfsx_ind … H) -L1 #L1 #HL1 #IHL1 #L2 #HL12
@@ -38,28 +37,42 @@ qed-.
 
 (* Advanced forward lemmas **************************************************)
 
-(* Basic_2A1: includes: lsx_fwd_bind_sn lsx_fwd_flat_sn *)
-(* Basic_2A1: was: lsx_fwd_pair_sn *)
+(* Basic_2A1: uses: lsx_fwd_pair_sn lsx_fwd_bind_sn lsx_fwd_flat_sn *)
 lemma lfsx_fwd_pair_sn: ∀h,o,I,G,L,V,T. G ⊢ ⬈*[h, o, ②{I}V.T] 𝐒⦃L⦄ →
                         G ⊢ ⬈*[h, o, V] 𝐒⦃L⦄.
 #h #o #I #G #L #V #T #H @(lfsx_ind … H) -L
 #L1 #_ #IHL1 @lfsx_intro
-#L2 #H #HnL12 elim (lfpx_pair_sn_split … o I … T H) -H
-/6 width=4 by lfsx_lfdeq_trans, lfdeq_trans, lfdeq_fwd_pair_sn/
+#L2 #H #HnL12 elim (lfpx_pair_sn_split … H o I T) -H
+/6 width=3 by lfsx_lfdeq_trans, lfdeq_trans, lfdeq_fwd_pair_sn/
 qed-.
 
-(* Basic_2A1: was: lsx_fwd_flat_dx *)
+(* Basic_2A1: uses: lsx_fwd_flat_dx *)
 lemma lfsx_fwd_flat_dx: ∀h,o,I,G,L,V,T. G ⊢ ⬈*[h, o, ⓕ{I}V.T] 𝐒⦃L⦄ →
                         G ⊢ ⬈*[h, o, T] 𝐒⦃L⦄.
 #h #o #I #G #L #V #T #H @(lfsx_ind … H) -L
 #L1 #_ #IHL1 @lfsx_intro
-#L2 #H #HnL12 elim (lfpx_flat_dx_split … o I … V … H) -H
-/6 width=4 by lfsx_lfdeq_trans, lfdeq_trans, lfdeq_fwd_flat_dx/
+#L2 #H #HnL12 elim (lfpx_flat_dx_split … H o I V) -H
+/6 width=3 by lfsx_lfdeq_trans, lfdeq_trans, lfdeq_fwd_flat_dx/
+qed-.
+
+(* Basic_2A1: uses: lsx_fwd_bind_dx *)
+(* Note: the exclusion binder (ⓧ) makes this more elegant and much simpler *)
+lemma lfsx_fwd_bind_dx: ∀h,o,p,I,G,L,V,T. G ⊢ ⬈*[h, o, ⓑ{p,I}V.T] 𝐒⦃L⦄ →
+                        G ⊢ ⬈*[h, o, T] 𝐒⦃L.ⓧ⦄.
+#h #o #p #I #G #L #V #T #H @(lfsx_ind … H) -L
+#L1 #_ #IH @lfsx_intro
+#L2 #H #HT elim (lfpx_bind_dx_split_void … H o p I V) -H
+/6 width=5 by lfsx_lfdeq_trans, lfdeq_trans, lfdeq_fwd_bind_dx_void/
 qed-.
 
 (* Advanced inversion lemmas ************************************************)
 
-(* Basic_2A1: was: lsx_inv_flat *)
+(* Basic_2A1: uses: lsx_inv_flat *)
 lemma lfsx_inv_flat: ∀h,o,I,G,L,V,T. G ⊢ ⬈*[h, o, ⓕ{I}V.T] 𝐒⦃L⦄ →
                      G ⊢ ⬈*[h, o, V] 𝐒⦃L⦄ ∧ G ⊢ ⬈*[h, o, T] 𝐒⦃L⦄.
 /3 width=3 by lfsx_fwd_pair_sn, lfsx_fwd_flat_dx, conj/ qed-.
+
+(* Basic_2A1: uses: lsx_inv_bind *)
+lemma lfsx_inv_bind: ∀h,o,p,I,G,L,V,T. G ⊢ ⬈*[h, o, ⓑ{p,I}V.T] 𝐒⦃L⦄ →
+                     G ⊢ ⬈*[h, o, V] 𝐒⦃L⦄ ∧ G ⊢ ⬈*[h, o, T] 𝐒⦃L.ⓧ⦄.
+/3 width=4 by lfsx_fwd_pair_sn, lfsx_fwd_bind_dx, conj/ qed-.