# Publications

We analyse the issue of firm-sponsored training under product market imperfections. In this setting, qualification becomes a public good for firms when their profits are increasing in the stock of skilled workers but remains a private good to students/workers. Students have to pay a tuition fee but at the same time firms sponsor education: universities sell training to both. We prove that the proportion of skilled workers is larger in more competitive economies/industries while the share of firms in the financing of training is a monotonically decreasing function of the degree of competition. An increase of the latter indeed increases the equilibrium skilled wage while reducing its sensitivity to an increase of the supply of skilled workers. The firms’ aggregate expenditures on training per worker are nevertheless a nonmonotonic function of the competitiveness of the economy.

We study an infinite horizon economy with a representative agent whose utility function includes consumption, real balances and leisure. Real balances enter the utility function pre-multiplied by a parameter reflecting the inverse of the degree of financial market imperfection, i.e. the inverse of the transaction costs justifying a positively valued fiat money. Indeterminacy arises both through a transcritical and a flip bifurcation: somewhat paradoxically, the amplitude of the indeterminacy region improves as soon as the degree of market imperfection is set lower and lower. Such results are robust with respect to the choice for the elasticity of the labor supply, both when the latter is set close to zero and to infinite. We also provide conditions for the existence, uniqueness and multiplicity of the steady states and finally, we asses the impact of the degree of market imperfection on the occurrence of such phenomena

We introduce two tests for the constancy of conditional correlations of unknown functional form in multivariate GARCH models. The first test is based on artificial neural networks and the second on a Taylor expansion of each unknown conditional correlation. They can be seen as general misspecification tests for a large set of multivariate GARCH-type models. We investigate their size and their power through Monte Carlo experiments. Moreover, we study the robustness of these tests to nonnormality by simulating some models, such as the GARCH - t and Beta - t - EGARCH. We give some illustrative empirical examples based on financial data. JEL: C22, C45, C58 / KEY WORDS: Multivariate GARCH, Neural Network, Taylor Expansion. RÉSUMÉ. Nous introduisons deux tests de constance des corrélations conditionnelles de forme fonctionnelle inconnue dans les modèles GARCH multivariés. Le premier test est basé sur les réseaux de neurones artificiels et le second sur un développement de Taylor de chaque corrélation conditionnelle inconnue. Ces tests peuvent ětre considérés comme des tests généraux de mauvaise spécification pour un grand nombre de modèles multivariés de type GARCH. Nous étudions leur taille et leur puissance par des expériences de Monte-Carlo. De plus, nous nous intéressons à la robustesse de ces tests à la non normalité en simulant certains modèles comme les modèles GARCH-t et beta-t-EGARCH. Nous donnons enfin quelques exemples empiriques illustratifs sur données financières.

During the last third of the twentieth century, political philosophers actively debated about the content of distributive justice; the ruling ethical view of utilitarianism was challenged by various versions of equality of opportunities. Economists formulated several ways of modeling these ideas, focusing upon how individuals are placed with respect to opportunities for achieving various outcomes, and what compensation is due to individuals with truncated opportunities. After presenting a review of the main philosophical ideas (section 2), we turn to economic models (sections 3 and 4). We propose a reformulation of the definition of economic development, replacing the utilitarian measure of GDP per capita with a measure of the degree to which opportunities for income acquisition in a nation have been equalized. Finally, we discuss issues that the econometrician faces in measuring inequality of opportunity, briefly review the empirical literature (section 6), and conclude (section 7).

This paper empirically examines the idea that Free Trade Agreements (FTAs) are more likely to be signed by governments playing ‘endgames’; that is, when governments are about to lose power. Two empirical strategies shed light on this hypothesis. One relies on events that increase the probability of political turnover, the other on term limits. I find that countries are more likely to sign FTAs after the unexpected exit of their leaders, when political instability is high. The key finding is partly confirmed in the term-limits strategy as governments are found to form more FTAs during their last term in office.

Rainwater harvesting, consisting in collecting runoff from precipitation, has been widely developed to stop groundwater declines and even raise water tables. However, this expected environmental effect is not self-evident. We show in a simple setting that the success of this conjunctive use depends on whether the runoff rate is above a threshold value. Moreover, the bigger the storage capacity, the higher the runoff rate must be to obtain an environmentally efficient system. We also extend the model to include other hydrological parameters and ecological damages, which respectively increase and decrease the environmental efficiency of rainwater harvesting.

The aim of this study was to investigate whether the labor market mobility of a population of cancer survivors 2 years after diagnosis differed compared to the French general population by focusing on

The purpose of this article is to offer a non-technical selective survey for a general audience about how economists have progressively handled the concept of equality of opportunity. The key idea is that equality of opportunity not only deals with ex-ante inequalities, something that the name already suggests, but also with ex-post inequalities which makes the analysis quite different from that of the capability approach. The article is structured in three parts. First, we review the main theoretical issues about inequality of opportunity. We then follow by looking at the measurement issues and by presenting some empirical results. We finally provide an overview about the challenges faced by policies aiming at enhancing equality of opportunity.

No abstract is available for this item.

We introduce within-group external effects in the two-sided singlehoming model of Armstrong (2006). First, we propose a general characterization of the platform access fees at the symmetric equilibrium of the game. Second, we combine this general formulation with a specific modeling of the relationship between buyers and sellers on B2C platforms, so as to analyze how changes in the underlying characteristics of the product market affect the equilibrium of the game. We show that sellers may be better off, and buyers worse off, in markets with more sellers. We also show that sellers and buyers prefer full product differentiation while platforms prefer no differentiation.