The fractal city theory revisited: new empirical evidence from the distribution of Romanian cities and towns.

Some of the main ideas of the fractal city theory are briefly reviewed, and their applicability is tested for the medium and small-size Romanian urban settlements. The universality of Zipf law for cities and towns distribution is proved once again and a stochastic master equation is proposed in order to explain the empirical distribution. The urban structure of Bucharest is investigated as an example of medium-size city formed by merging some independent poles of growth. The Central Places Theory is found to be in disagreement with the real urban structure. Instead, the diffusion-limited aggregation and self-organized criticality mechanisms are investigated by means of some numerical simulations and are found to fit better the urban perimeter growth.