Set Difference as Intersection with Complement

Theorem
$$A - B = A \cap \mathcal{C} \left({B}\right)$$

Proof
This follows directly from Set Difference Relative Complement: $$A - B = A \cap \mathcal{C}_S \left({B}\right)$$. Simply let $$S = \mathbb{U}$$, and since $$A,B\in\mathbb{U}$$ by the definition of the universe, the result follows.