\begin{definition}[Definition:Convolution of Real Sequences]
Let $\sequence f$ and $\sequence g$ be real sequences.
The '''convolution''' of $f$ and $g$ is defined as:
:$\displaystyle \sequence {f_i} * \sequence {g_i} := \sum_{j \mathop \in \Z_{\ge 0} } f_i g_{i - j}$
\end{definition}