The trawl function is parametrised by the two parameters \(H> 1\)
and \(\alpha > 0\) as follows: $$g(x) = (1-x/\alpha)^{-H},
\mbox{ for } x \le 0.$$ If \(H \in (1,2]\), then the resulting trawl
process has long memory, for \(H>2\), it has short memory.