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

Theorem
Let $T_1, T_2$ be subsets of a universe $\mathbb U$.

Then:
 * $\overline {T_1 \cup T_2} = \overline T_1 \cap \overline T_2$

where $\overline T_1$ is the set complement of $T_1$.

It is arguable that this notation may be easier to follow:


 * $\map \complement {T_1 \cup T_2} = \map \complement {T_1} \cap \map \complement {T_2}$