Let Σ = {a, b}. For a word w ∈ Σ* , let na(x) denote the number of a’s in w and let nb(x) denote the number of b’s in w. Consider the following language:
L := {xy | x, y ∈ Σ* , na(x) = nb(y)}
What can we say about L?
|
|
|
(A) L is regular, but not context-free.
|
|
(B) L is context-free, but not regular.
|
|
(C) L is Σ*.
|
|
(D) None of these.
|