  Given, a sequence $\mathcal{X}$ of $n$ variables, a time-series constraint
ctr using the Sum aggregator, and a sliding time-series constraint enforcing
the constraint ctr on each sliding window of $\mathcal{X}$ of $m$ consecutive
variables, we describe a $\Theta(n)$ time complexity checker, as well as a
$\Theta(n)$ space complexity reformulation for such sliding constraint.
