X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Fetc%2Fynat%2Fynat_plus.etc;fp=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Fetc%2Fynat%2Fynat_plus.etc;h=e535b9fe00858af5e2c484de128c45eb22152b88;hb=68b4f2490c12139c03760b39895619e63b0f38c9;hp=0000000000000000000000000000000000000000;hpb=1fd63df4c77f5c24024769432ea8492748b4ac79;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/ground/etc/ynat/ynat_plus.etc b/matita/matita/contribs/lambdadelta/ground/etc/ynat/ynat_plus.etc
new file mode 100644
index 000000000..e535b9fe0
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/ground/etc/ynat/ynat_plus.etc
@@ -0,0 +1,4 @@
+
+lemma pippo: ∀x,y. x + y ≤ x → x = ∞ ∨ y = 0.
+/3 width=1 by discr_yplus_xy_x, yle_antisym/ qed-.
+