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...

The quantity theory is disjunct to the hard core of general equilibrium theory. It does not relate to the formal foundations of standard economics and, vice versa, from the behavioral axioms of standard economics a rationale for using money cannot be derived. The present paper leaves the...

The equalization of profit rates as the outcome of free competition is one of the oldest tenets in theoretical economics. Being intuitively convincing its premises and implications, though, are not well defined. As Walras put it: ‘To state a theory is one thing; to prove it is another.’...