hws/hw02.tex
changeset 931 14a6adca16b8
parent 928 2f3c077359c4
child 941 66adcae6c762
equal deleted inserted replaced
930:0fe0937e049d 931:14a6adca16b8
   202 
   202 
   203 \item Give a regular expression over the alphabet $\{a,b\}$
   203 \item Give a regular expression over the alphabet $\{a,b\}$
   204       recognising all strings that do not contain any
   204       recognising all strings that do not contain any
   205       substring $bb$ and end in $a$.
   205       substring $bb$ and end in $a$.
   206 
   206 
   207       \solution{$((ba)^* \cdot (a)^*)^*\,\cdot\,a$}
   207       \solution{$((ba)^* \cdot (a)^*)^*\,\cdot\,a + ba$ \quad Not sure whether this can be simplified.}
   208 
   208 
   209 \item Do $(a + b)^* \cdot b^+$ and $(a^* \cdot b^+) +
   209 \item Do $(a + b)^* \cdot b^+$ and $(a^* \cdot b^+) +
   210   (b^*\cdot b^+)$ define the same language?
   210   (b^*\cdot b^+)$ define the same language?
   211 
   211 
   212   \solution{No, the first one can match for example abababababbbbb
   212   \solution{No, the first one can match for example abababababbbbb