X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fstatic%2Flfxs_fqup.ma;h=50fb764fa197601c152bdf5d92024186d287bc8b;hb=c3832abc23bb0907df2deb6751f4a46d213675b7;hp=62c5b056494e65cab5f0a644ee707a07819d9f4a;hpb=e39d1924cd572acdf0cf8dba08f3b650dfd6abee;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_fqup.ma b/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_fqup.ma
index 62c5b0564..50fb764fa 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_fqup.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/static/lfxs_fqup.ma
@@ -22,3 +22,11 @@ include "basic_2/static/lfxs.ma".
 lemma lfxs_refl: ∀R. (∀L. reflexive … (R L)) → ∀L,T. L ⦻*[R, T] L.
 #R #HR #L #T elim (frees_total L T) /3 width=3 by lexs_refl, ex2_intro/
 qed.
+
+lemma lfxs_pair: ∀R. (∀L. reflexive … (R L)) →
+                 ∀L,V1,V2. R L V1 V2 → ∀I,T. L.ⓑ{I}V1 ⦻*[R, T] L.ⓑ{I}V2.
+#R #HR #L #V1 #V2 #HV12 #I #T
+elim (frees_total (L.ⓑ{I}V1) T) #f #Hf
+elim (pn_split f) * #g #H destruct
+/4 width=3 by lexs_refl, lexs_next, lexs_push, ex2_intro/
+qed.