Relative Complement of Cartesian Product

Theorem
Let $A$ and $B$ be sets.

Let $X \subseteq A$ and $Y \subseteq B$.

Then:
 * $\complement_{A \mathop \times B} = \left({A \times \complement_B \left({Y}\right)}\right) \cup \left({\complement_A \left({X}\right) \times B}\right)$