ABSTRACT
Understanding how urban systems evolve is important to make good plans for urban developments. In recent years, the impact of the sciences of complexity pervades in many fields. There is a resurgence of attempts in the literature of the explanations of how the Zipf law, or the power law in general, emerges in natural systems. The power law is one of such self-organizing phenomena. In nature, occurrences and scales of earthquakes and meteorites appear to obey a power law and so do stock markets in the social science. Zipf's rank-size rule is an example of power law, relating the sizes of cities to their ranks. The power law is a general phenomenon seen in many natural and social settings, including urban systems, as was discussed by Krugman. Krugman (1996) considers Simon's model as one of the best explanations of how the power law emerges.
