X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Frelocation%2Fxap.ma;h=0835ec53f5326d518fb4194b861542bc5312c70e;hp=0f367b218935fe30bb24078908b49b3e678c10d5;hb=d06053844638d88936d711b66fddbcca2a9add1c;hpb=9e31ac1f3f868349154b0ce2e550e2476aaf6a30

diff --git a/matita/matita/contribs/lambdadelta/ground/relocation/xap.ma b/matita/matita/contribs/lambdadelta/ground/relocation/xap.ma
index 0f367b218..0835ec53f 100644
--- a/matita/matita/contribs/lambdadelta/ground/relocation/xap.ma
+++ b/matita/matita/contribs/lambdadelta/ground/relocation/xap.ma
@@ -82,3 +82,9 @@ lemma tr_nap_plus (f) (m) (n):
       ⇂*[↑n]f＠❨m❩+f＠§❨n❩ = f＠§❨m+n❩.
 /2 width=1 by eq_inv_nsucc_bi/
 qed.
+
+lemma tr_xap_pos (f) (n):
+      n = ↑↓n → f＠❨n❩=↑↓(f＠❨n❩).
+#f #n #H0 >H0 -H0
+<tr_xap_ninj <nsucc_pnpred //
+qed.