update in delayed_updating

[helm.git] / matita / matita / contribs / lambdadelta / delayed_updating / substitution / lift_prototerm.ma

diff --git a/matita/matita/contribs/lambdadelta/delayed_updating/substitution/lift_prototerm.ma b/matita/matita/contribs/lambdadelta/delayed_updating/substitution/lift_prototerm.ma
index 9193260452841583ff83da63e3f76f9c72a68ff5..4a0615a3ca081265e256e54a4cb683ef7810e351 100644 (file)
--- a/matita/matita/contribs/lambdadelta/delayed_updating/substitution/lift_prototerm.ma
+++ b/matita/matita/contribs/lambdadelta/delayed_updating/substitution/lift_prototerm.ma
@@ -26,4 +26,10 @@ interpretation
 
 lemma in_comp_lift_bi (f) (p) (t):
       p ϵ t → ↑[f]p ϵ ↑[f]t.
-/2 width=1 by subset_in_ext_f1_dx/ qed.
+/2 width=1 by subset_in_ext_f1_dx/
+qed.
+
+lemma eq_lift_bi (f) (t1) (t2):
+      t1 ⇔ t2 → ↑[f]t1 ⇔ ↑[f]t2.
+/2 width=1 by subset_equivalence_ext_f1_bi/
+qed.