X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Ftutorial%2Fchapter12.ma;h=07a5fd19f04586d76a2bfa627ede33b789a69c9d;hb=74c6905907b0bca229366d52450e2a6982b5b8be;hp=72e396c133ea84026a0898fae69eb4069d488eef;hpb=a57efb7e02d1c0af621ab36bd345f2f79f063a0c;p=helm.git

diff --git a/matita/matita/lib/tutorial/chapter12.ma b/matita/matita/lib/tutorial/chapter12.ma
index 72e396c13..07a5fd19f 100644
--- a/matita/matita/lib/tutorial/chapter12.ma
+++ b/matita/matita/lib/tutorial/chapter12.ma
@@ -16,6 +16,7 @@ include "basics/relations.ma".
 include "basics/types.ma".
 include "arithmetics/nat.ma".
 include "hints_declaration.ma".
+include "basics/core_notation/invert_1.ma".
 
 (******************* Quotienting in type theory **********************)