Definition 5.1.6 (Borel Measure).label Let $(X,\cali{T})$ be a topological space and $(X,\Si,\mu)$ be a measure space then $\mu$ is a Borel measure if $\Si=\cali{B}_{X}$. Denote by $\cali{M}_{lf}(X)$ the space of Borel measures on $X$ that is finite on compact sets.