update in standard library

[helm.git] / matita / matita / lib / tutorial / chapter12.ma

diff --git a/matita/matita/lib/tutorial/chapter12.ma b/matita/matita/lib/tutorial/chapter12.ma
index 72e396c133ea84026a0898fae69eb4069d488eef..07a5fd19f04586d76a2bfa627ede33b789a69c9d 100644 (file)
--- 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 **********************)