Hi,
Is the following a context-free language?
L = {a_concate_n_w_w_concate_R_a_concate_n | n ≥ 0, w ∈ {a, b}*}
or L = {a^n w w^R a^n |.......}

I think no because the number of w's is not equal.

Somebody please guide me.

Zulfi.

 

What do you mean that the number of w's is not equal?

 

Hi,
One is w and the other is w_concate_R. I got the answer. Actually w_concate_R is the reverse of w. So its fine. It is context free. I got confused initially. I thought they are concatenated different number of times.
Zulfi.