The modern literature on city formation and development, for example the New Economic Geography literature, has studied the agglomeration of agents in size or mass. We investigate agglomeration in sorting or by type of worker, that implies agglomeration in size when worker populations differ by...

Baldwin et al. (2003) show that the famous tomahawk bifurcation, which is used by Fujita et al. (1999) to explain the formation of the core-periphery pattern, disappears when two regions have uneven agricultural populations. Thus, this type of bifurcations result from intrinsic model symmetry....

We study the indeterminacy of equilibrium in the Fujita-Krugman model of city formation under monopolistic competition and increasing returns. Both the number and the locations of cities are endogenously determined. Assuming smooth transportation costs, we examine equilibria in city-economies...