diff -r 1da2cfd1ca45 -r 900cf45ff0a6 src/HOL/document/root.tex
--- a/src/HOL/document/root.tex	Sun Apr 10 11:42:07 2005 +0200
+++ b/src/HOL/document/root.tex	Sun Apr 10 17:19:03 2005 +0200
@@ -3,6 +3,7 @@
 
 \documentclass[11pt,a4paper]{article}
 \usepackage{graphicx,isabelle,isabellesym,latexsym}
+\usepackage{amssymb}
 \usepackage[only,bigsqcap]{stmaryrd}
 \usepackage[latin1]{inputenc}
 \usepackage{pdfsetup}