779 \item A regular expression for email addresses

   779 \item A regular expression for email addresses

   780 

   780 

   781 \begin{center}

   781 \begin{center}

   782 \begin{tabular}{l}

   782 \begin{tabular}{l}

   783 (name: \bl{$[a\mbox{-}z0\mbox{-}9\_\!\_\,.-]^+$})\bl{$\cdot @\cdot$}\\ 

   783 (name: \bl{$[a\mbox{-}z0\mbox{-}9\_\!\_\,.-]^+$})\bl{$\cdot @\cdot$}\\ 

   785 \qquad\qquad(top\_level: \bl{$[a\mbox{-}z\,.]^{\{2,6\}}$})

   785 \qquad\qquad(top\_level: \bl{$[a\mbox{-}z\,.]^{\{2,6\}}$})

   786 \end{tabular}

   786 \end{tabular}

   787 \end{center}

   787 \end{center}

   788 

   788 

   789 \bl{\[

   789 \bl{\[