Let $M = (X, \mathcal{F}, \mu)$ be a D1158: Measure space.
Let $E, F \in \mathcal{F}$ each be a D1109: Measurable set in $M$ such that
Let $E, F \in \mathcal{F}$ each be a D1109: Measurable set in $M$ such that
(i) | \begin{equation} \mu(E), \mu(F) < \infty \end{equation} |
Then
\begin{equation}
\mu(E \cup F)
= \mu(E) + \mu(F) - \mu(E \cap F)
\end{equation}