599 We represented the ``n-times'' \bl{$a^{\{n\}}$} as a 

   599 We represented the ``n-times'' \bl{$a^{\{n\}}$} as a 

   600 sequence regular expression:

   600 sequence regular expression:

   601 

   601 

   602 \begin{center}

   602 \begin{center}

   603 \begin{tabular}{rl}

   603 \begin{tabular}{rl}

   604 1: & \bl{$a$}\\

   605 1: & \bl{$a$}\\

   605 2: & \bl{$a\cdot a$}\\

   606 2: & \bl{$a\cdot a$}\\

   606 3: & \bl{$a\cdot a\cdot a$}\\

   607 3: & \bl{$a\cdot a\cdot a$}\\

   607 & \ldots\\

   608 & \ldots\\

   608 13: & \bl{$a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a$}\\

   609 13: & \bl{$a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a\cdot a$}\\

   771     ytick={0,10,...,30},

   772     ytick={0,10,...,30},

   772     scaled ticks=false,

   773     scaled ticks=false,

   773     axis lines=left,

   774     axis lines=left,

   774     width=9cm,

   775     width=9cm,

   775     height=5.5cm, 

   776     height=5.5cm, 

   777     legend pos=north west,

   778     legend pos=north west,

   778     legend cell align=left]

   779     legend cell align=left]

   779 \addplot[blue,mark=*, mark options={fill=white}] table {re-python2.data};

   780 \addplot[blue,mark=*, mark options={fill=white}] table {re-python2.data};

   780 \addplot[cyan,mark=*, mark options={fill=white}] table {re-java.data};

   781 \addplot[cyan,mark=*, mark options={fill=white}] table {re-java.data};

   781 \addplot[red,mark=*, mark options={fill=white}] table {re-js.data};

   782 \addplot[red,mark=*, mark options={fill=white}] table {re-js.data};

   782 \end{axis}

   784 \end{axis}

   783 \end{tikzpicture}

   785 \end{tikzpicture}

   784 \end{center}

   786 \end{center}

   785 

   787 

   786 Regex: \bl{$(a^*)^* \cdot b$}

   788 Regex: \bl{$(a^*)^* \cdot b$}