ThmDex – An index of mathematical definitions, results, and conjectures.
▼ Set of symbols
▼ Alphabet
▼ Deduction system
▼ Theory
▼ Zermelo-Fraenkel set theory
▼ Set
▼ Subset
▼ Power set
▼ Hyperpower set sequence
▼ Hyperpower set
▼ Hypersubset
▼ Subset algebra
▼ Boolean algebra
▼ Sigma-algebra
▼ Set of sigma-algebras
Definition D318
Generated sigma-algebra
Formulation 0
Let $X$ be a D11: Set such that
(i) $\mathfrak{S} : = \mathfrak{S}(X)$ is the D484: Set of sigma-algebras on $X$
(ii) $\mathcal{S} \subseteq \mathcal{P}(X)$ is a D3367: Subset algebra on $X$
The generated sigma-algebra on $X$ with generator $\mathcal{S}$ is the D11: Set \begin{equation} \sigma \langle \mathcal{S} \rangle : = \bigcap \{ \mathcal{F} : \mathcal{S} \subseteq \mathcal{F} \in \mathfrak{S} \} \end{equation}
Formulation 1
Let $X$ be a D11: Set such that
(i) $\mathcal{S} \subseteq \mathcal{P}(X)$ is a D3367: Subset algebra on $X$
The generated sigma-algebra on $X$ with generator $\mathcal{S}$ is the D11: Set \begin{equation} \sigma \langle \mathcal{S} \rangle : = \bigcap \{ \mathcal{F} : \mathcal{S} \subseteq \mathcal{F} \text{ and } \mathcal{F} \text{ is a sigma-algebra on } X \} \end{equation}
Children
▶ D319: Borel sigma-algebra
▶ D3889: Tail sigma-algebra