This is a short essay on open questions in urban economic theory.

We criticize the theories used to explain the size distribution of cities. They take an empirical fact and work backward to obtain assumptions on primitives. The induced theoretical assumptions on consumer behavior, particularly about their inability to insure against the city-level productivity...

The tomahawk bifurcation is used by Fujita et al. (1999) in a model with two regions to explain the formation of a core-periphery urban pattern from an initial uniform distribution. Baldwin et al. (2003) show that the tomahawk bifurcation disappears when the two regions have an uneven population...

The long-term trends of urbanization suggest: not only have more cities formed, but the leading metropolises have grown larger, with a number of peripheral subcenters developing over time. Conventional models of urban growth are limited, in that commuting cost and congestion eventually result in...

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...

Canonical analysis of the classical general equilibrium model demonstrates the existence of an open and dense subset of standard economies that possess fully-revealing rational expectations equilibria. This paper shows that the analogous result is not true in urban economies. An open subset of...

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...

This paper presents a micro-model of knowledge creation and transfer for a couple. Our model incorporates two key aspects of the cooperative process of knowledge creation: (i) heterogeneity of people in their state of knowledge is essential for successful cooperation in the joint creation of new...

We consider the role of the nonlinear commuting cost function in determination of the equilibrium commuting pattern where all agents are mobile. Previous literature has considered only linear commuting cost, where in equilibrium, all workers are indifferent about their workplace location. We...

We consider the optimal nonlinear income taxation problem in a dynamic, stochastic environment when the government cannot change the tax rule as uncertainty resolves. Due to such a stationarity constraint, our taxation problem is reduced to a static one over an expanded type space. We strengthen...