(i) | $\mathsf{SA} = \mathsf{SA}(X)$ is the D484: Set of sigma-algebras on $X$ |
(ii) | $\mathcal{F} \in \mathsf{SA}$ is a D84: Sigma-algebra on $X$ |
(i) | $\mathsf{SA} = \mathsf{SA}(X)$ is the D484: Set of sigma-algebras on $X$ |
(ii) | $\mathcal{F} \in \mathsf{SA}$ is a D84: Sigma-algebra on $X$ |