Let $P = (\Omega, \mathcal{F}, \mathbb{P})$ be a D1159: Probability space such that
(i) | $F, E_0, E_1, E_2, \ldots \in \mathcal{F}$ are each an D1716: Event in $P$ |
(ii) | $E_0, E_1, E_2, \ldots $ is a D83: Proper set partition of $\Omega$ |
(iii) | \begin{equation} \mathbb{P}(E_0), \mathbb{P}(E_1), \mathbb{P}(E_2), \ldots > 0 \end{equation} |
(iv) | $\mathcal{G} := \sigma \langle E_0, E_1, E_2, \ldots \rangle$ is a D318: Generated sigma-algebra on $\Omega$ with generators $E_0, E_1, E_2, \ldots$ |
Then
\begin{equation}
\forall \, n \in \mathbb{N} \text{ and } \omega \in \Omega
\left( \omega \in E_n \quad \implies \quad \mathbb{P}(F \mid \mathcal{G}) (\omega) \overset{a.s.}{=} \frac{\mathbb{P} (F \cap E_n)}{\mathbb{P}(E_n)} \right)
\end{equation}