De Morgan's Laws (Set Theory)/Set Complement/General Case/Complement of Union

Theorem
Let $\mathbb T$ be a set of sets, all of which are subsets of a universe $\mathbb U$.

Then:
 * $\displaystyle \complement \left({\bigcup \mathbb T}\right) = \bigcap_{H \mathop \in \mathbb T} \complement \left({H}\right)$