\begin{definition}[Definition:Measurable Function/Positive]
Let $\struct {X, \Sigma}$ be a measurable space. 
Let $S \in \set {\R, \overline \R}$. 
Let $f : X \to S$ be a $\Sigma$-measurable function.
We say that $f$ is a '''positive $\Sigma$-measurable function''' {{iff}}: 
:$f \ge 0$
where $\ge$ denotes pointwise inequality.
Category:Definitions/Measurable Functions
\end{definition}