Hi,

I have following language. I have to determine, if its context free or not.

L = {a^n b^j a^k b^l : n+j ≤ k+l}.

When n+j== k+l then it seems context free because we push 'n' number of 'a's and 'j' number of 'b's. We can cancel out with equal number of 'a's and 'b's if n+j == k+l. But if (n+j) < (k+l) then the stack would be empty but the other after the mid-point still exists. So the strings are not balance. So what we can say about this language?

Zulfi.

I have following language. I have to determine, if its context free or not.

L = {a^n b^j a^k b^l : n+j ≤ k+l}.

When n+j== k+l then it seems context free because we push 'n' number of 'a's and 'j' number of 'b's. We can cancel out with equal number of 'a's and 'b's if n+j == k+l. But if (n+j) < (k+l) then the stack would be empty but the other after the mid-point still exists. So the strings are not balance. So what we can say about this language?

Zulfi.

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