Let f be a measurable, real function defined in a neighbourhood of infinity. The function f is said to be of generalised regular variation if there exist functions h 6? 0 and g 0 such that f(xt) ? f(t) = h(x)g(t) + o(g(t)) as t ? ? for all x ? (0,?). Zooming in on the remainder term o(g(t))...