Set Difference is Disjoint with Reverse

Theorem

 * $\left({S \setminus T}\right) \cap \left({T \setminus S}\right) = \varnothing$

Proof
We assume that $S, T \subseteq \mathbb U$ where $\mathbb U$ is the universe.

Then we can use the definition of Set Difference as Intersection with Complement.