X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fstatic%2Flfxs_length.ma;h=5f8b62e081f0a4d899a6af62356b725665435ce2;hb=47a745462a714af9d65cea7b61af56524bd98fa1;hp=01dd82cf42db896041fc8516a95986b8a5743b90;hpb=e39d1924cd572acdf0cf8dba08f3b650dfd6abee;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 01dd82cf4..5f8b62e08 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_length.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_length.ma
@@ -13,12 +13,37 @@
 (**************************************************************************)
 
 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 ****)
 
 (* Forward lemmas with length for local environments ************************)
 
-lemma lfxs_fwd_length: ∀R,L1,L2,T. L1 ⦻*[R, T] L2 → |L1| = |L2|.
+(* Basic_2A1: uses: llpx_sn_fwd_length *)
+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-.
+
+(* Inversion lemmas with length for local environment ***********************)
+
+lemma lfxs_inv_zero_length: ∀R,Y1,Y2. Y1 ⪤*[R, #0] Y2 →
+                            ∨∨ Y1 = ⋆ ∧ Y2 = ⋆
+                             | ∃∃I,L1,L2,V1,V2. L1 ⪤*[R, V1] L2 & R L1 V1 V2 &
+                                                Y1 = L1.ⓑ{I}V1 & Y2 = L2.ⓑ{I}V2
+                             | ∃∃I,L1,L2. |L1| = |L2| & Y1 = L1.ⓤ{I} & Y2 = L2.ⓤ{I}.
+#R #Y1 #Y2 #H elim (lfxs_inv_zero … H) -H *
+/4 width=9 by lexs_fwd_length, ex4_5_intro, ex3_3_intro, or3_intro2, or3_intro1, or3_intro0, conj/
+qed-.