Abstract
It is believed in urban economics that a polycentric urban configuration emerges only when the multiple-types of agents compete for land (Fujita and Thisse, 2002, p.209). This paper discloses that the polycentric urban configuration emerges in a single-type agent model. We also show that the dispersion force with a spill-over effect and its distance decay property are necessary for the emergence of the polycentric configuration. To show this, we compare two types of social interaction models, SI model and SISC model, each of which has a different dispersion force: the former model's dispersion force consists of land rent, and the latter consists of spatial competition. The analysis of two models proves that the polycentric configuration emerges in the SISC model, while this configuration never emerges in the SI model.
