Let $M = (X, \mathcal{F})$ be a D1108: Measurable space such that
(i) | $E_0, E_1, E_2, \ldots \in \mathcal{F}$ are each a D1109: Measurable set in $M$ |
Then
(1) | \begin{equation} \bigcap_{n = 1}^{\infty} \bigcup_{m = n}^{\infty} E_m \in \mathcal{F} \end{equation} |
(2) | \begin{equation} \bigcup_{n = 1}^{\infty} \bigcap_{m = n}^{\infty} E_m \in \mathcal{F} \end{equation} |