update in delayed-updating

[helm.git] / matita / matita / contribs / lambdadelta / delayed_updating / syntax / prototerm.ma

diff --git a/matita/matita/contribs/lambdadelta/delayed_updating/syntax/prototerm.ma b/matita/matita/contribs/lambdadelta/delayed_updating/syntax/prototerm.ma
index 79452e39e54edf049a54d95984f5da8765eb1c4a..30a2770e279bceb6c3baa14bcd51e0dcc570a789 100644 (file)
--- a/matita/matita/contribs/lambdadelta/delayed_updating/syntax/prototerm.ma
+++ b/matita/matita/contribs/lambdadelta/delayed_updating/syntax/prototerm.ma
@@ -42,3 +42,11 @@ lemma prototerm_in_comp_root (p) (t):
       p ϵ t → p ϵ ▵t.
 /2 width=2 by ex_intro/
 qed.
+
+(* Basic destructions *******************************************************)
+
+lemma prototerm_in_root_append_des_sn (t) (p) (q):
+      p●q ϵ ▵t → p ϵ ▵t.
+#t #p #q * #r #Hr
+/2 width=2 by ex_intro/
+qed-.