\begin{module}[id=functions]%
\symdef[assocarg=1]{cart}[1]{\assoc[p=500]{\times}{#1}}%
\symdef{fun}[3]{\mixfixiii[p=200]{}{#1}{\colon}{#2}{\rightarrow}{#3}{}}%
\symdef{inset}[2]{\infix[p=650]{\in}{#1}{#2}}%
\end{module}%
