\begin{definition}[Definition:Convolution Integral/Positive Real Domain]
Let $f$ and $g$ be functions which are integrable.
Let $f$ and $g$ be supported on the positive real numbers $\R_{\ge 0}$ only.
The '''convolution integral''' of $f$ and $g$ may be defined as:
:$\ds \map f t * \map g t := \int_0^t \map f u \map g {t - u} \rd u$
\end{definition}