\prelimsec{Miscellaneous notation}
-We write $\Func{D}{R}$ for the set of all functions with domain $D$ and range
-$R$.
+We write $\#S$ for the cardinality of a set $S$. We write $\Func{D}{R}$ for
+the set of all functions with domain $D$ and range $R$.
\prelimsec{Groups}