--- a/document/root.tex	Fri Jan 11 13:18:33 2013 +0000
+++ b/document/root.tex	Sat Jan 12 01:05:01 2013 +0000
@@ -21,6 +21,8 @@
 \renewcommand{\isasymemptyset}{$\varnothing$}
 \renewcommand{\isacharunderscore}{\mbox{$\_$}}
 \renewcommand{\isasymiota}{}
+\newcommand{\isasymulcorner}{$\ulcorner$}
+\newcommand{\isasymurcorner}{$\urcorner$}
 \begin{document}
 
 \title{Formalising Computability Theory in Isabelle/HOL}