Hallo,
I have an enlarged sigma-field $\displaystyle \sigma(\mathcal{F}\vee \sigma(X))$ (that is the smallest sigma-field containing the sigma-fields $\displaystyle \mathcal{F} \text{ and }\sigma(X)$?
How does the generator of this (enlarged) sigma-field look like?
Is this sigma-field generated by sets of the form $\displaystyle \{A \cap B: A \in\mathcal{F},B \in \sigma(X)\}$,
i.e.
$\displaystyle \sigma(\{A \cap B: A \in\mathcal{F},B \in \sigma(X)\})=\sigma(\mathcal{F}\vee \sigma(X))$?

Thanks in advance