hws/hw05.tex
changeset 619 136517d67d40
parent 602 9aa901039e33
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   105 \item[$\bullet$] $b$
   105 \item[$\bullet$] $b$
   106 \item[$\bullet$] $ab$
   106 \item[$\bullet$] $ab$
   107 \item[$\bullet$] $ba$
   107 \item[$\bullet$] $ba$
   108 \item[$\bullet$] $bb$
   108 \item[$\bullet$] $bb$
   109 \item[$\bullet$] $baa$
   109 \item[$\bullet$] $baa$
   110 \end{itemize}  
   110 \end{itemize}
       
   111 
       
   112 \item Suppose the following context-free grammar 
       
   113   
       
   114   \begin{plstx}[margin=1cm]
       
   115   : \meta{S\/} ::= a\cdot \meta{S\/}\cdot a\;\mid\;
       
   116                    b\cdot \meta{S\/}\cdot b\;\mid\; \epsilon\\
       
   117   \end{plstx}
       
   118 
       
   119 Describe which language is generated by this grammar.
       
   120   
   111 
   121 
   112 
   122 
   113 \item {\bf(Optional)} Recall the definitions for $Der$ and $der$
   123 \item {\bf(Optional)} Recall the definitions for $Der$ and $der$
   114       from the lectures. Prove by induction on $r$ the
   124       from the lectures. Prove by induction on $r$ the
   115       property that 
   125       property that