On the evolution of hierarchical urban systems

The rapid urbanization trend of the world economy implies an increasing imp ortance of cities as basic units of national and international trade. Given that the cities within an economy constitute some form of hierarchical str ucture, we model the endogenous formation of a hierarchical urban system. T o overcome the multiplicity of equilibria, we propose an evolutionary appro ach which combines a general equilibrium model with an adjustment dynamics. It is demonstrated that as the economy's population size increases gradual ly, the urban system self-organizes into a highly regular hierarchical syst em a la Christaller. (C) 1999 Elsevier Science B.V. All rights reserved. JE L classification: R11; F12; D5.