POWER-LAW SCALING FOR A SYSTEM OF INTERACTING UNITS WITH COMPLEX INTERNAL STRUCTURE

We study the dynamics of a system composed of interacting units each w ith a complex internal structure comprising many subunits and treat th e case in which each subunit grows in a multiplicative manner. We prop ose a model for such systems in which the interaction among the units is treated in a mean field approximation and the interaction among sub units is nonlinear. We test the model and find agreement between our p redictions and empirical results based on a large economics database s panning 20 years.