etnms/etnms.tex
changeset 122 dc0cdfc5fc66
parent 121 df9e966ecb6d
child 123 fb7472a29058
equal deleted inserted replaced
121:df9e966ecb6d 122:dc0cdfc5fc66
  1200 This list is then "flattened"--$\ZERO$ will be
  1200 This list is then "flattened"--$\ZERO$ will be
  1201 thrown away by $\textit{flatten}$; $ _0(_0\ONE  + _{11}a^*)$
  1201 thrown away by $\textit{flatten}$; $ _0(_0\ONE  + _{11}a^*)$
  1202 is opened up to make the list consisting of two separate elements 
  1202 is opened up to make the list consisting of two separate elements 
  1203 $_{00}\ONE$ and $_{011}a^*$, note that $flatten$ 
  1203 $_{00}\ONE$ and $_{011}a^*$, note that $flatten$ 
  1204 $\fuse$s the bit(s) $_0$ to the front of $_0\ONE $ and $_{11}a^*$.
  1204 $\fuse$s the bit(s) $_0$ to the front of $_0\ONE $ and $_{11}a^*$.
  1205 In a nutshell, the order of simplification causes
  1205 The order of simplification, which impacts the order that alternatives
       
  1206 are  opened up, causes
  1206 the bits to be moved differently.
  1207 the bits to be moved differently.
  1207  
  1208  
  1208  \subsubsection{A Failed Attempt To Remedy the Problem Above}
  1209  \subsubsection{A Failed Attempt To Remedy the Problem Above}
  1209 A simple class of regular expression and string
  1210 A simple class of regular expression and string
  1210 pairs $(r, s)$ can be deduced from the above example 
  1211 pairs $(r, s)$ can be deduced from the above example 
  1370 for the counterexample where 
  1371 for the counterexample where 
  1371 \begin{center}
  1372 \begin{center}
  1372 $r$ is the regular expression
  1373 $r$ is the regular expression
  1373 $(ab+(a^*+aa))$ and $s$  is the string $aa$
  1374 $(ab+(a^*+aa))$ and $s$  is the string $aa$
  1374 \end{center}
  1375 \end{center}
  1375 $\rup\backslash_{simp} \, s \neq \simp(\rup\backslash s)$
  1376 
  1376 happens again, whereas this does not happen for the old
  1377 \noindent
       
  1378 $\rup\backslash_{simp} \, s$ is equal to 
       
  1379 $ _0(_0\ONE  + _{11}a^*)$
       
  1380 $\rup\backslash_{simp} \, s \neq \simp(\rup\backslash s)$,
       
  1381  whereas this does not happen for the old
  1377 version of $\simp$.
  1382 version of $\simp$.
       
  1383 We have changed the algorithm to suppress the old
       
  1384 counterexample, but this gives rise to new counterexamples.
  1378 This dilemma causes this amendment not a successful 
  1385 This dilemma causes this amendment not a successful 
  1379 attempt to make $\rup\backslash_{simp} \, s = \simp(\rup\backslash s)$
  1386 attempt to make $\rup\backslash_{simp} \, s = \simp(\rup\backslash s)$
  1380 under every possible regular expression and string.
  1387 under every possible regular expression and string.
  1381 \subsection{Properties of the Function $\simp$}
  1388 \subsection{Properties of the Function $\simp$}
  1382 
  1389