X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fstatic%2Flfxs_length.ma;h=2a090e642c83d2c55dd75863dae8c05f03d303f1;hb=c879284b576409cec07e96c1f08510d9d9ac14f3;hp=3b8208e4a78c46dad67083b49c796bfd3647ca5f;hpb=e11ce46390f264e9010157dd36c0b9e71a58ba4b;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_length.ma b/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_length.ma
index 3b8208e4a..2a090e642 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_length.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_length.ma
@@ -13,7 +13,7 @@
 (**************************************************************************)
 
 include "basic_2/relocation/lexs_length.ma".
-include "basic_2/static/lfxs.ma".
+include "basic_2/static/lfxs_drops.ma".
 
 (* GENERIC EXTENSION ON REFERRED ENTRIES OF A CONTEXT-SENSITIVE REALTION ****)
 
@@ -23,3 +23,16 @@ include "basic_2/static/lfxs.ma".
 lemma lfxs_fwd_length: ∀R,L1,L2,T. L1 ⪤*[R, T] L2 → |L1| = |L2|.
 #R #L1 #L2 #T * /2 width=4 by lexs_fwd_length/
 qed-.
+
+(* Properties with length for local environments ****************************)
+
+(* Basic_2A1: uses: llpx_sn_lift_le llpx_sn_lift_ge *)
+lemma lfxs_lifts_bi: ∀R.d_liftable2_sn … lifts R →
+                     ∀L1,L2. |L1| = |L2| → ∀K1,K2,T. K1 ⪤*[R, T] K2 →
+                     ∀b,f. ⬇*[b, f] L1 ≡ K1 → ⬇*[b, f] L2 ≡ K2 →
+                     ∀U. ⬆*[f] T ≡ U → L1 ⪤*[R, U] L2.
+#R #HR #L1 #L2 #HL12 #K1 #K2 #T * #f1 #Hf1 #HK12 #b #f #HLK1 #HLK2 #U #HTU
+elim (frees_total L1 U) #f2 #Hf2
+lapply (frees_fwd_coafter … Hf2 … HLK1 … HTU … Hf1) -HTU #Hf
+/4 width=12 by lexs_length_cfull, lexs_liftable_co_dedropable_bi, cext2_d_liftable2_sn, cfull_lift_sn, ex2_intro/
+qed-.