An extension of Berge's Maximum Theorem is given, with two different topologies on the choice set used for the two semicontinuity assumptions on preferences. It is used to establish the norm-to-weak* continuity of (truncated) excess-demand, announced without proof by Jones (1986). This...

Rational expectations as the standard solution concept for dynamic economic models leaves open two fundamental questions: (1) how can RE be attained if agents do not actually begin with RE?, and (2) which RE solution will the economy follow hen there are multiple RE solutions? Expectational...

I study a matching model where heterogeneous firms publicly announce wage offers. A Walrasian type of equilibrium is derived, and the concept of stability used to restrict the set of equilibria. It is shown that the equilibrium is always separable, with high productivity firms announcing...

Large public bureaucracies are usually less efficient than modern private corporations. This paper explains how the degree of discretionary power might account for this difference in efficiency. In fact, increasing the discretionary power of the intermediate layers of an organization can enhance...

There are two parts to this paper. Part One introduces the subject of implementation, and provides applications (in particular, to the theory of contracts). This part is written so as to be accessible to the general reader. Part Two surveys the literature, and is somewhat more formal.

This paper extends the classic two-armed bandit problem to a many-agent setting in which N players each face the same experimentation problem. The difference with the single-agent problem is that agents can now learn from the experiments of others. Thus, experiementation produces a public good...

It has been argued that collusion among the members of an organization or a vertical structure creates efficiency losses, and hence should be prevented. This paper shows that whenever collusion takes the form of co-insurance agreements, here called ?friendships?, among the members of a vertical...

We study wage determination in a job-matching model, under the assumption that wages may be continuously renegotiated, so as to reflect the employee's endogenous outside option. We characterize the unique equilibirum of the model and we analyse the distribution of producer surplus. The model is...

Using subdifferentials we develop a marginal-analytical approach to equilibrium and use it in the commodity space L? to derive new results on the representation of prices by a density. Apart from conferring advantages when the intepretation of prices as marginal costs is required, the calculus...