Self Doubt

Question

L= {a^nb^2nc^n| n>=0}

 

Isn't, it CFL ????

Comments

No, it's not. For $a^ib^jc^k$, we have to compare $i=2*j$ and $2*j=k$. Cannot be done with a single stack

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But consider that procedure,

Push all the a's in the stack and when the first b comes start poping a's after that when the stack becomes empty then start pushing the b's into the stack and finally when c comes start poping the b's too. If finally the stack is empty then language is accepted otherwise not...

What i am wrong please mention.

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$a^3b^8c^5$ you procedure will accept this string, but it doesn't belong to the language.

What you are checking is if $a^ib^jc^k$ then $i+k=j$

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ok, Got It Thanks, Brother.  :)