Ambiguity aversion and the absence of wage indexation

This paper analyzes optimal wage contracting assuming agents are not subjective expected utility maximizers but are, instead, ambiguity (or uncertainty) averse decision makers who maximize Choquet expected utility. We show that such agents will choose not to include any indexation coverage in their wage contracts even when inflation is uncertain, unless the perceived inflation uncertainty is high enough. Significantly, the exercise does not presume any exogenous costs (e.g., transactions costs) of including indexation links.     

On multiple equilibria and the rational expectations hypothesis?

Summary. This paper analyzes through a simple two-period model the fact that, if some agents hold inside money intertemporally, the second-period “normalization” matters. Thus, there are several equilibria of the second-period economy, indexed by the level of inflation. A concept of equilibrium acknowledging this fact, and requiring that agents put some weight on any of the possible second-period equilibrium price vectors is developed. Such an equilibrium is shown to exist, and is illustrated by an example.     

The Geopolitics of Protected Areas

ABSTRACT

The conservation enterprise is embedded in ideas of the environment through which it promotes a vision of the world and the relations between the non-human and human. The papers in this forum analyse conservation from various vantage points to draw the links between geopolitics and conservation. The authors use three themes to demonstrate these links. The first theme draws on the concept of environmentality to show the mobilization of ecological rationalities and power towards the creation of protected areas. The second pays attention to networks formed across the distance, and how they influence the location and governance of protected areas. The third focuses on the strategies the conservation lobby uses to align local identities with global conservation ideals and goals. Collectively, these themes highlight features of conservation geopolitics.     

Diversification, convex preferences and non-empty core in the Choquet expected utility model

Summary. We show, in the Choquet expected utility model, that preference for diversification, that is, convex preferences, is equivalent to a concave utility index and a convex capacity. We then introduce a weaker notion of diversification, namely “sure diversification.” We show that this implies that the core of the capacity is non-empty. The converse holds under concavity of the utility index, which is itself equivalent to the notion of comonotone diversification, that we introduce. In an Anscombe-Aumann setting, preference for diversification is equivalent to convexity of the capacity and preference for sure diversification is equivalent to non-empty core. In the expected utility model, all these notions of diversification are equivalent and are represented by the concavity of the utility index. Received: July 27, 1999; revised version: November 7, 2000     

On multiple equilibria and the rational expectations hypothesis

Summary This paper analyzes through a simple two-period model the fact that, if some agents hold inside money intertemporally, the second-period normalization matters. Thus, there are several equilibria of the second-period economy, indexed by the level of inflation. A concept of equilibrium acknowledging this fact, and requiring that agents put some weight on any of the possible second-period equilibrium price vectors is developed. Such an equilibrium is shown to exist, and is illustrated by an example.This a revised version of chapter three of my Ph.D. dissertation. I would like to thank David Cass, Atsushi Kajii, George Mailath and Shinichi Suda for helpful discussions and comments. Thanks are also due to Jean-Michel Grandmont who pointed out mistakes in a previous version. All remaining mistakes are of course my own. Financial support from a CARESS scholarship at the University of Pennsylvania is gratefully acknowledged.     

Attitudes Towards Foreign Products and Welfare with Capital Mobility

We develop a model of trade with imperfect competition to study the welfare implications in developing and developed countries of the asymmetry in attitudes towards foreign products. In the developed country, consumers benefit from a better perception of foreign products while the rental rate of capital declines as long as the location of capital remains unchanged. However, when capital is mobile, the developing country hosts more and more capital at the expense of the developed country as perception of varieties produced in the developed country improves and the surplus of consumers in the developed country can decrease.     

Invariances and Diversities in the Patterns of Industrial Evolution: Some Evidence from Italian Manufacturing Industries

This work explores and compares some basic properties of corporate growth process at both aggregate manufacturing level and disaggregated sectoral levels. Using an extensive dataset on Italian manufacturing firms, we investigate which properties of firm growth dynamics are robust under disaggregation. We compare the results obtained with three different definitions of firm size, namely total sales, number of employees and value added. Our analysis suggests that while different sectors are characterized by significant differences in firm size distributions, in the degrees of concentration and in the autoregressive structure of the growth processes, there are also regularities which hold across all of them, such as the approximate unit root nature of the growth process and the power exponential shape of the growth rates density. Together, these “stylized facts” suggest challenging puzzles on the drivers of corporate growth and the resulting industrial structures.     

Traders' Bidding Strategies on European Grain Export Refunds: An Analysis with Affiliated Signals

Using a multivariate distribution of traders' information with correlations, we specify the traders' bidding strategies on tenders of European soft wheat intervention stocks. We show that correlations may have opposing effects on the traders' bidding strategy, depending on their valuation of the grain. This structural approach allows us to estimate the traders' strategies using generalized method of moments procedures.