\section{Absolutely Continuous}
\label{section:absolutely-continuous-measure}

\begin{definition}[Absolutely Continuous]
\label{definition:absolutely-continuous}
    Let $(X, \cm)$ be a measurable space and $\mu, \nu$ be signed/vector measures on $X$, then $\nu$ is \textbf{absolutely continuous} with respect to $\mu$, denoted $\nu \ll \mu$, if every $\mu$-null set is $\nu$-null.
\end{definition}