On Dec 08 2000, Hubert Chan wrote:
> Oops.  There should be a "| \epsilon" at the end of that (where
> \epsilon is the empty string) if you count the empty string as a
> palindrome.  If not, then you should add "| aa | bb".

        No, it's not the same thing. The former language generated by
        the grammar with the production S -> \varepsilon has the empty
        string, while, if you substitute it by S -> aa | bb, then your
        new language does not contain \varepsilon.


        []s, Roger...

-- 
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  Rogerio Brito - [EMAIL PROTECTED] - http://www.ime.usp.br/~rbrito/
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