Publications

La plupart des informations présentées ci-dessous ont été récupérées via RePEc avec l'aimable autorisation de Christian Zimmermann
An inertial proximal point method for difference of maximal monotone vector fields in Hadamard manifoldsJournal articleJoão S. Andrade, Jurandir de O. Lopes et João Carlos de Souza, Journal of Global Optimization, Forthcoming

We propose an inertial proximal point method for variational inclusion involving difference of two maximal monotone vector fields in Hadamard manifolds. We prove that if the sequence generated by the method is bounded, then every cluster point is a solution of the non-monotone variational inclusion. Some sufficient conditions for boundedness and full convergence of the sequence are presented. The efficiency of the method is verified by numerical experiments comparing its performance with classical versions of the method for monotone and non-monotone problems.

Can labour market institutions mitigate the China syndrome? Evidence from regional labour markets in EuropeJournal articleJan-Luca Hennig, The World Economy, Volume n/a, Issue n/a, Forthcoming

This paper investigates how labour market regulations alter the adverse impact of rising import competition from China in European local labour markets between 1997 and 2006. The paper constructs measures of regional exposure to Chinese imports based on previous literature and on regional labour market frictions exploiting involuntary labour reallocations. Taking into account the endogeneity of import competition and its interaction with labour market regulations, the paper finds that regions more exposed to the rise of China have suffered from a reduction in manufacturing employment shares. This shock grows larger with regional labour market frictions; hence, it exacerbates the impact of trade shock on employment. Moreover, the paper finds that employment in public services, and not in construction or private services sector, absorbed the negative shock to the manufacturing sector. The unemployment rate, the labour force participation rate and wages in all sectors are unresponsive to import competition from China.

The Regularity of the Value Function of Repeated Games with Switching CostsJournal articleYevgeny Tsodikovich, Xavier Venel et Anna Zseleva, Mathematics of Operations Research, Forthcoming

We study repeated zero-sum games where one of the players pays a certain cost each time he changes his action. We derive the properties of the value and optimal strategies as a function of the ratio between the switching costs and the stage payoffs. In particular, the strategies exhibit a robustness property and typically do not change with a small perturbation of this ratio. Our analysis extends partially to the case where the players are limited to simpler strategies that are history independent―namely, static strategies. In this case, we also characterize the (minimax) value and the strategies for obtaining it.

Spatial PolarizationJournal articleFabio Cerina, Elisa Dienesch, Alessio Moro et Michelle Rendall, The Economic Journal, Forthcoming

We document the emergence of spatial polarisation in the United States during the 1980–2008 period. This phenomenon is characterised by stronger employment polarisation in larger cities, both at the occupational and the worker levels. We quantitatively evaluate the role of technology in generating these patterns by constructing and calibrating a spatial equilibrium model. We find that faster skill-biased technological change in larger cities can account for a substantial fraction of spatial polarisation in the United States. Counterfactual exercises suggest that the differential increase in the share of low-skilled workers across city size is due mainly to the large demand by high-skilled workers for low-skilled services and, to a smaller extent, to the higher complementarity between low- and high-skilled workers in production relative to middle-skilled workers.

Nursing homes and mortality in Europe: Uncertain causalityJournal articleXavier Flawinne, Mathieu Lefebvre, Sergio Perelman, Pierre Pestieau et Jérôme Schoenmaeckers, Health Economics, Volume n/a, Issue n/a, Forthcoming

The current health crisis has particularly affected the elderly population. Nursing homes have unfortunately experienced a relatively large number of deaths. On the basis of this observation and working with European data (from SHARE), we want to check whether nursing homes were lending themselves to excess mortality even before the pandemic. Controlling for a number of important characteristics of the elderly population in and outside nursing homes, we conjecture that the difference in mortality between those two samples is to be attributed to the way nursing homes are designed and organized. Using matching methods, we observe excess mortality in Sweden, Belgium, Germany, Switzerland, Czech Republic and Estonia but not in the Netherlands, Denmark, Austria, France, Luxembourg, Italy and Spain. This raises the question of the organization and management of these nursing homes, but also of their design and financing.

The environmental justice implications of the Paris low emission zone: a health and economic impact assessmentJournal articleErika Moreno, Lara Schwartz, Sabine Host, Olivier Chanel et Tarik Benmarhnia, Air Quality, Atmosphere & Health, Forthcoming

Background:
Reducing the mortality burden associated with urban air pollution constitutes a public health priority, and evidence of unequal exposure and susceptibility across population subgroups is growing. Many European countries have implemented low emission zones (LEZs) in densely populated city centers. Although LEZs decrease air pollution exposure and health impacts, evidence is lacking on their impact across neighborhoods and socio-economic groups.
Objectives:
The aim of this study was to evaluate the most equitable approach to implementing the second phase of the LEZ in Paris, France. We also present a literature review of the studies evaluating the benefits associated with LEZs in Europe.
Methods:
A health impact assessment (HIA) was conducted to quantify changes in air pollution exposure and expected health benefits by socioeconomic group and neighborhood related to four hypothetical scenarios for the second phase of the LEZ based on French Deprivation Index scores. The study focused on NO2 and PM2.5 as air pollutants and evaluated the impact of the LEZ on the inequitable burden of childhood asthma and all-cause premature adult mortality. We also conducted an economic evaluation associated with the LEZ benefits on prevented deaths and asthma cases.
Results:
The scenario with the largest LEZ perimeter and the most stringent vehicle standards prevented the highest number of cases and produced the most equitable distribution of health benefits, especially childhood asthma. It is expected that 810 deaths and 3200 cases of asthma could be prevented from the LEZ extension in this scenario. These results were distributed heterogeneously across three socioeconomic (SES) groups, most noticeably with asthma cases as 230, 180, and 210 cases were avoided per 100,000 inhabitants in high, medium, and low SES groups, respectively. We found substantial economic benefits associated with LEZ, with estimates ranging from €0.76 billion to €2.36 billion for prevented deaths. The benefits associated with asthma reduction ranged from €2.3 million to €8.3 million.
Discussion:
Conducting HIAs with a focus on equity will further inform policy makers of the impact of LEZ models on air pollution, health, and environmental justice. Developing these systematic methods and applying them to future LEZs and other air pollution policies will increase their effectiveness to reduce the burden of ambient air pollution on society and the environment.

Private Exploitation of the North-Western Sahara Aquifer SystemJournal articleAmine Chekireb, Julio Goncalves, Hubert Stahn et Agnès Tomini, Environmental Modeling & Assessment, Forthcoming

We formulate a hydro-economic model of the North-Western Sahara Aquifer System (NWSAS) to assess the effects of intensive pumping on the groundwater stock and examine the subsequent consequences of aquifer depletion. This large system comprises multi-layer reservoirs with vertical exchanges, all exploited under open access properties. We first develop a theoretical model to account for relevant features of the NWSAS by introducing, in the standard Gisser-Sanchez model, a non-stationary demand and quadratic stock-dependent cost functions. In the second step, we calibrate parameters values using data from the NWSAS over 1955–2000. We finally simulate the time evolution of the aquifer system with exploitation under an open-access regime. We specifically examine time trajectories of the piezometric levels in the two reservoirs, the natural outlets, and the modification of water balances. We find that natural outlets of the two reservoirs might be totally dried before 2050.

General Versions of the Ekeland Variational Principle: Ekeland Points and Stop and Go DynamicsJournal articleLe Phuoc Hai, Phan Quoc Khanh et Antoine Soubeyran, Journal of Optimization Theory and Applications, Forthcoming

We establish general versions of the Ekeland variational principle (EVP), where we include two perturbation bifunctions to discuss and obtain better perturbations for obtaining three improved versions of the principle. Here, unlike the usual studies and applications of the EVP, which aim at exact minimizers via a limiting process, our versions provide good-enough approximate minimizers aiming at applications in particular situations. For the presentation of applications chosen in this paper, the underlying space is a partial quasi-metric one. To prove the aforementioned versions, we need a new proof technique. The novelties of the results are in both theoretical and application aspects. In particular, for applications, using our versions of the EVP together with new concepts of Ekeland points and stop and go dynamics, we study in detail human dynamics in terms of a psychological traveler problem, a typical model in behavioral sciences.

Equilibrium set-valued variational principles and the lower boundedness condition with application to psychologyJournal articleJing-Hui Qiu, Antoine Soubeyran et Fei He, Optimization, pp. 1-33, Forthcoming

We first give a pre-order principle whose form is very general. Combining the pre-order principle and generalized Gerstewitz functions, we establish a general equilibrium version of set-valued Ekeland variational principle (denoted by EVP), where the objective function is a set-valued bimap defined on the product of quasi-metric spaces and taking values in a quasi-ordered linear space, and the perturbation consists of a subset of the ordering cone multiplied by the quasi-metric. From this, we obtain a number of new results which essentially improve the related results. Particularly, the earlier lower boundedness condition has been weakened. Finally, we apply the new EVPs to Psychology.

Other-regarding preferences and giving decision in a risky environment: experimental evidenceJournal articleMickael Beaud, Mathieu Lefebvre et Julie Rosaz, Review of Economic Design, Forthcoming

We investigate whether and how an individual giving decision is affected in risky environments in which the recipient’s wealth is random. We demonstrate that, under risk neutrality, the donation of dictators with a purely ex post view of fairness should, in general, be affected by the riskiness of the recipient’s payoff, while dictators with a purely ex ante view should not be. Furthermore, we observe that some influential inequality aversion preferences functions yield opposite predictions when we consider ex post view of fairness. Hence, we report on dictator games laboratory experiments in which the recipient’s wealth is exposed to an actuarially neutral and additive background risk. Our experimental data show no statistically significant impact of the recipient’s risk exposure on dictators’ giving decisions. This result appears robust to both the experimental design (within subjects or between subjects) and the origin of the recipient’s risk exposure (chosen by the recipient or imposed on the recipient). Although we cannot sharply validate or invalidate alternative fairness theories, the whole pattern of our experimental data can be simply explained by assuming ex ante view of fairness and risk neutrality.