From Local to Global Competition

We introduce a framework that has known models of oligopolistic competition with differentiated products (the circle and the constant elasticity of substitution (CES)) as limit cases. This integrative approach incorporates both localized and global competition, as well as price-sensitive individual demands. It is used to consider the qualitative impact of major changes over the last two centuries: reduction in transport costs, increased taste for variety, population growth, and use of technologies with greater returns to scale. We work out the properties of an extended Chamberlinian model that should be useful both in industrial organization and urban economics.