--- a/preamble.tex	Tue May 25 16:50:55 2010 -0700
+++ b/preamble.tex	Thu May 27 14:04:06 2010 -0700
@@ -13,6 +13,7 @@
 
 \usepackage[section]{placeins}
 \usepackage{leftidx}
+\usepackage{stmaryrd} % additional math symbols, e.g. \mapsfrom
 
 \SelectTips{cm}{}
 % This may speed up compilation of complex documents with many xymatrices.