--- a/preamble.tex	Wed Jun 02 12:52:08 2010 -0700
+++ b/preamble.tex	Wed Jun 02 16:51:40 2010 -0700
@@ -190,6 +190,8 @@
 \newcommand{\CD}[1]{C_*(\Diff(#1))}
 \newcommand{\CH}[1]{C_*(\Homeo(#1))}
 
+\newcommand{\cl}[1]{\underrightarrow{#1}}
+
 \newcommand{\directSumStack}[2]{{\begin{matrix}#1 \\ \DirectSum \\#2\end{matrix}}}
 \newcommand{\directSumStackThree}[3]{{\begin{matrix}#1 \\ \DirectSum \\#2 \\ \DirectSum \\#3\end{matrix}}}