Jean-Michel Ghez , Enzo Orlandini , Maria-Carla Tesi , Sandro Vaienti Dynamical integral transform on fractal sets and the computation of entropy (50K, TeX) ABSTRACT. We introduce an integral transform of wavelet type, which we call Dynamical Integral Transform, and we show that it can be used to compute the 2-nd Renyi entropy for a large class of invariant measures. The method is then generalized to the whole spectrum of the Renyi entropies and establishes a correspondance between thermodynamic formalism and the Dynamical Integral Transform of expanding strange sets. Numerical examples are presented.