X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Frelocation%2Flexs_length.ma;h=71467ba72319444401782e16aa8ef9d32d1c7392;hb=5c186c72f508da0849058afeecc6877cd9ed6303;hp=c8d3536de1c6c53cabf21c13fc0dbb65cc8c00d7;hpb=bb6e68b2cf746bb3108543807207a1ca628ab442;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/relocation/lexs_length.ma b/matita/matita/contribs/lambdadelta/basic_2/relocation/lexs_length.ma
index c8d3536de..71467ba72 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/relocation/lexs_length.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/relocation/lexs_length.ma
@@ -12,14 +12,35 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include "basic_2/grammar/lenv_length.ma".
+include "basic_2/syntax/lenv_length.ma".
 include "basic_2/relocation/lexs.ma".
 
-(* GENERAL ENTRYWISE EXTENSION OF A CONTEXT-SENSITIVE REALTION FOR TERMS ****)
+(* GENERIC ENTRYWISE EXTENSION OF CONTEXT-SENSITIVE REALTIONS FOR TERMS *****)
 
-(* Forward lemmas on length for local environments **************************)
+(* Forward lemmas with length for local environments ************************)
 
-(* Basic_2A1: includes: lpx_sn_fwd_length *)
-lemma lexs_fwd_length: ∀RN,RP,L1,L2,f. L1 ⦻*[RN, RP, f] L2 → |L1| = |L2|.
-#RM #RP #L1 #L2 #f #H elim H -L1 -L2 -f //
+lemma lexs_fwd_length: ∀RN,RP,f,L1,L2. L1 ⪤*[RN, RP, f] L2 → |L1| = |L2|.
+#RN #RP #f #L1 #L2 #H elim H -f -L1 -L2 //
+#f #I1 #I2 #L1 #L2 >length_bind >length_bind //
 qed-.
+
+(* Properties with length for local environments ****************************)
+
+lemma lexs_length_cfull: ∀L1,L2. |L1| = |L2| → ∀f. L1 ⪤*[cfull, cfull, f] L2.
+#L1 elim L1 -L1
+[ #Y2 #H >(length_inv_zero_sn … H) -Y2 //
+| #L1 #I1 #IH #Y2 #H #f
+  elim (length_inv_succ_sn … H) -H #I2 #L2 #HL12 #H destruct
+  elim (pn_split f) * #g #H destruct /3 width=1 by lexs_next, lexs_push/
+]
+qed.
+
+lemma lexs_length_isid: ∀R,L1,L2. |L1| = |L2| →
+                        ∀f. 𝐈⦃f⦄ → L1 ⪤*[R, cfull, f] L2.
+#R #L1 elim L1 -L1
+[ #Y2 #H >(length_inv_zero_sn … H) -Y2 //
+| #L1 #I1 #IH #Y2 #H #f #Hf
+  elim (length_inv_succ_sn … H) -H #I2 #L2 #HL12 #H destruct
+  elim (isid_inv_gen … Hf) -Hf #g #Hg #H destruct /3 width=1 by lexs_push/
+]
+qed.