It is shown that the multifractal property is shared by both Lyapunov expon
ents and dual Lyapunov exponents related to scaling functions of one-dimens
ional expanding folding maps. This reveals in a quantitative way the comple
xity of the dynamics determined by such maps. (C) 1999 American Institute o
f Physics. [S1054-1500(99)00204-9].