diff -r ada83e7228eb -r 7b0a43bdd3c4 preamble.tex
--- a/preamble.tex	Tue Jul 01 01:53:15 2008 +0000
+++ b/preamble.tex	Tue Jul 01 04:00:22 2008 +0000
@@ -117,6 +117,7 @@
 \newcommand{\onto}{\twoheadrightarrow}
 \newcommand{\iso}{\cong}
 \newcommand{\actsOn}{\circlearrowright}
+\newcommand{\isoto}{\xrightarrow{\iso}}
 
 \newcommand{\htpy}{\simeq}