U= {a, b, c, d, e, f, g, h}

A= {a, c, f, g}

B= {a, e}

C= {b, h}

compute: $\displaystyle \overline{C}\cap\overline{C}$

(the complement line is supposed to go over the whole thing but i didn't know how to do that, oops ^^)

i just started discrete math so the answer might be easy, but how is it not just the empty set? how can you intersect the complement of something with itself? any help would be appreciated, thanks =)