--- a/doc/tutorial/source/replace.txt	Fri Aug 02 12:31:16 2013 -0700
+++ b/doc/tutorial/source/replace.txt	Fri Aug 02 14:08:36 2013 -0700
@@ -1,3 +1,5 @@
 .. |ns3| replace:: *ns-3*
 
 .. |ns2| replace:: *ns-2*
+
+.. |check| replace:: :math:`\checkmark`