--- a/Pearl-jv/document/root.tex	Wed May 04 15:27:04 2011 +0800
+++ b/Pearl-jv/document/root.tex	Mon May 09 04:46:43 2011 +0100
@@ -5,6 +5,7 @@
 \usepackage{amsmath}
 \usepackage{amssymb}
 \usepackage{mathabx}
+\usepackage{proof}
 \usepackage{longtable}
 \usepackage{graphics}
 \usepackage{pdfsetup}