Monotone continuous multiple priors

Summary. In a multiple priors model á la Gilboa and Schmeidler (1989), we provide necessary and sufficient behavioral conditions ensuring the countable additivity and non-atomicity of all priors.Received: 25 November 2002, Revised: 24 June 2004, JEL Classification Numbers: D81.We thank Roko Aliprantis, Maristella Botticini, Erio Castagnoli, Larry Epstein, Paolo Ghirardato, Itzhak Gilboa, Luigi Montrucchio, David Schmeidler, Marciano Siniscalchi, an Associate Editor, and an anonymous referee for helpful discussions. Fabio Maccheroni and Massimo Marinacci gratefully acknowledge the financial support of MIUR and NOMOS Sistema (Milano).     

How Long is a Piece of Cable? Equilibrium Determination of Local Telephone Areas

This paper studies the endogenous determination of telephone local calling areas. In many telephone systems, calls between users in the same calling area are local; calls to outside the calling area are long distance and priced differently. We allow the extension of this area to be treated as a strategic variable. We show the extension of the calling areas which maximizes the carrier's profit to be the same which a welfare maximizing regulator would choose. Under a price cap regime in which prices are required to meet an average price constraint, the firm manipulates strategically the extension of the local calling areas. We end the paper by considering the case of a competitive market. In this case, again, the owner of the local loop extends the local calling areas in response to decreased efficiency or increased competition of its competitors. Received April 25, 2002; revised version received September 9, 2002 Published online: April 30, 2003     

Growth and Unemployment: Towards a Theoretical Integration

We observe in the literature of the past decade some innovative contributions identified a relation between economic growth and long run unemployment. This set of contributions is composed of very few elements, all characterized by a high degree of heterogeneity about their features and about their final results.
In the first part of the survey we provide a classification of these early contributions. In the second part we explore some alternative formulations of the problem and we present a wider set of models displaying interesting features, able to promote further studies about the persistence of unemployment in a growing economy.     

Similarities and convergence in G-7 cycles

This paper examines the properties of G-7 cycles using a multicountry Bayesian panel VAR model with time variations, unit specific dynamics and cross-country interdependences. We demonstrate the presence of a significant world cycle and show that country specific indicators play a much smaller role. We detect differences across business cycle phases but, apart from an increase in synchronicity in the late 1990s, find little evidence of major structural changes. We also find no evidence of the existence of a Euro specific cycle or of its emergence in the late 1990s.     

Financial contagion and the role of the central bank

We investigate the role of a central bank (CB) in preventing and avoiding financial contagion. The CB, by imposing reserve requirements on the banking system, trades off the cost of reducing the resources available for long-term investment with the benefit of raising liquidity to face an adverse shock that could cause contagious crises. We argue that contagion is not due to the structure of the interbank deposit market, but to the impossibility to sign contracts contingent on unforeseen contingencies. As long as incomplete contracts are present, the CB may have a useful role in curbing contagion. Moreover, the CB allows the banking system to reach first-best allocation in all the states of the world when the notion of incentive-efficiency is considered. If the analysis is restricted to constrained-efficiency, the CB still avoids contagion without, however, reaching first-best consumption allocation. The model provides a rationale for reserve requirements without the presence of fiat money or asymmetric information.     

Endogenous employment rate in the efficiency wage shirking approach

The aim of New Keynesian theorists is to obtain Keynesian results on the basis of maximizing behavior. Accordingly, the New Keynesian shirking models depict a world of fully rational maximizing agents where equilibrium unemployment is the main consequence of the payment of efficiency wages. The problem is that oversimplified nature of most shirking models has until now prevented a full investigation of the interdependence of unemployment, the effort supplied by workers and labor demand. This article shows that the existence of this interdependence weakens the whole approach. In particular, when the unemployment rate is considered a truly endogenous variable, the stability of the macroeconomic equilibrium is generally incompatible with the existence of unemployment ascribed to the fact that firms pay efficiency wages.