Borel σ-algebra

Definition (Borel σ-algebra)

Let (X,T)(X,\mathscr{T}) be a Topological Space. Let B(X)\mathcal{B}(X) be the Smallest σ-algebra containing T.\mathscr{T}. Elements of B(X)\mathcal{B}(X) are called Borel subsets and B(X):=σ(T)\mathcal{B}(X):=\sigma(\mathscr{T})

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