First, I am not sure how to type the correct characters into this message block. I tried character map, but I had no luck. IF anyone wants to tell me if there is a language pack or add-on for this, feel free. Now the proof I am working on is as follows:

prove that if and only if "the complement of B" "the complement of A"

Can someone point me in the right direction? Again any help inputting the symbols is appreciated as well.