Publications
In this chapter, we revisit the origins and genesis of the french school of proximity and its evolution trough time, in order to better understand how and why the small group of researchers who were the driving force of this new way of thinking were quickly able to get a real legitimacy and effective recognition. First of all, it was clear that the role of space in economic dynamics was too often the subject of confusion and abusive assertions. Asking this question in terms of coordination made it possible to consider non-spatial factors in the analysis. The notion of proximity as a polysemic concept therefore opened the way to understanding how space matters or not, together with these other factors thus a renewed approach of questions related to space and territories. But, even starting from issues of economic nature, such an approach could not remain limited to its economic dimension, the questions of coordination involving social individuals, located in geographical space but also embedded in bundles of relationships and in institutions. Thus, it had to broaden very quickly to other disciplines in social sciences which largely contributed to consolidate the bases of what became a multidisciplinary approach and to develop theoretical as well as empirical tools.
We construct a spatiotemporal frame for the study of spatial economic and ecological patterns generated by transboundary pollution. Space is continuous and polluting emissions originate in the intensity of use of the production input. Pollution flows across locations following a diffusion process. The objective functional of the economy is to set the optimal production policy over time and space to maximize welfare from consumption, taking into account a negative local pollution externality and the diffusive nature of pollution. Our framework allows for space and time dependent preferences and productivity, and does not restrict diffusion speed to be space-independent. Accordingly, we develop a methodology to investigate the environmental and economic implications of spatiotemporal heterogeneity. We propose a method for an analytical characterization of the optimal paths. An application to technological spillovers is proposed for illustration. We focus on the determination of the optimal short-term spatiotemporal dynamics induced by the resulting non-autonomous problems.
We compare distributions of body mass index (BMI) categories among genders in France, the United States, and the United Kingdom on the basis of efficiency and inequality considerations. The new normative criteria that we propose are well suited to the ordinal nature of this variable. Our empirical results, which are supported by robust statistical inference, are twofold. First, BMI categories for the two genders are better distributed in France than in the UK, and in the UK than in the US. Second, BMI categories happen to be more equally distributed among men than among women in all three countries.
This paper provides a tool to build climate change scenarios to forecast Gross Domestic Product (GDP), modelling both GDP damage due to climate change and the GDP impact of mitigating measures. It adopts a supply-side, long-term view, with 2060 and 2100 horizons. It is a global projection tool (30 countries/regions), with assumptions and results both at the world and the country/regional level. Five different types of energy inputs are taken into account according to their CO2 emission factors. Full calibration is possible at each stage, with estimated or literature-based default parameters. Compared to other models, it provides a comprehensive modelisation of Total Factor Productivity (TFP), which is the most significant determinant of the GDP projected path. We present simulation results of different energy policy scenarios. They illustrate both the “tragedy of the horizon” and the “tragedy of the commons”, which call for a policy framework that adequately integrates a long run perspective, through a low-enough discount rate and an effective intergenerational solidarity as well as international cooperation.
Using a change in EU food aid policy in 1996 as an instrument for EU food aid allocation, I investigate how other donors react to the EU’s food aid allocation. At that time, the EU suddenly divided by two the number of its food aid recipients. On average, other donors imitate the EU at both extensive and intensive margins. Donors’ reactions are heterogeneous: European countries and Canada herd the EU, while the World Food Programme substitutes. The USA do not react. Those results can be explained by competition for relative impact and information effects. For a recipient country who constantly received food aid from the EU before 1996, the number of donors decreases by almost 0.5. This behavior reinforces the problem of orphan and darling recipients.
This paper has two aspects. Mathematically, in the context of global optimization, it provides the existence of an optimum of a perturbed optimization problem that generalizes the celebrated Ekeland variational principle and equivalent formulations (Caristi, Takahashi), whenever the perturbations need not satisfy the triangle inequality. Behaviorally, it is a continuation of the recent variational rationality approach of stay (stop) and change (go) human dynamics. It gives sufficient conditions for the existence of traps in a changing environment. In this way it emphasizes even more the striking correspondence between variational analysis in mathematics and variational rationality in psychology and behavioral sciences.
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