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International audience; The study analyses unintentional home and leisure injuries (HLIs) for the French senior population using data from the 2012 wave of the French health, health care and insurance survey. The results of our logit models reveal that health status, age, and risky attitudes are the main characteristics associated with HLIs for older people. When the severity of injuries is taken into consideration, the highest exposure to HLIs concerns the oldest seniors, aged 85 years old or older, with deteriorated health. This result is confirmed in the case of severe indoor HLIs, whereas for severe outdoor injuries, the most vulnerable individuals seem to be younger seniors, that is, 75–79 years old. Moreover, our findings suggest that HLIs, and mainly severe home HLIs, generate a short-term influence on a person's health.

International audience; This paper examines an explanatory policy in the management of drinking water in Tunisia. Indeed, the price variable, while is considered, in general way, as a confident indicator in the regulation of drinking water consumption, it seems to be insufficient since the management of drinking water is influenced by other set of variables such as: the revenue level of households, the consumption of bottled water, the alternative sources, the household size and, above all, the quality variable, which presents an enormous variability inter- and intra-regions. Through our study, we have shown, that the variation in willingness to pay (WTP) is essentially due to psychological and subjective consideration (the degree of importance of these variables in the scale of preferences of consumers).

The unit value of a commodity that Michio Morishima's method and its variations enable to determine correctly, is the sum of the value of the commodities it contains (inputs) and the quantity of labor required for its production. However, goods are sold at their market production price only when they meet a solvent social need that involves the entire economy with its interconnections between the different industrial sectors. This condition gives full meaning to Marx's fundamental equalities, which derive from the law of value and constitute invariants that apply to the economy as a whole. These equalities are necessary to determine market production prices. We demonstrate that they also enable to solve the transformation problem for a simple reproduction system without fixed capital by starting from Morishima's formalism and returning to a formalism closer to that used by Marx., Comment: 34 pages

The Casas-Alvero conjecture predicts that every univariate polynomial over a field of characteristic zero having a common factor with each of its derivatives $H_i (f )$ is a power of a linear polynomial. One approach to proving the conjecture is to first prove it for polynomials of some small degree $d$, compile a list of bad primes for that degree (namely, those primes p for which the conjecture fails in degree $d$ and characteristic $p$) and then deduce the conjecture for all degrees of the form $dp^\ell$ , $\ell \in \mathbb{N}$, where $p$ is a good prime for $d$. In this paper we calculate certain distinguished monomials appearing in the resultant $R(f, H_i (f ))$. As a corollary, we obtain a (non-exhaustive) list of bad primes for every degree $d \in \mathbb{N} \setminus 0$.

International audience; Workforce vulnerability has recently come to the forefront in European policy debate as countries searched for the potential engine of inclusive growth with an aim of protecting workers against adverse working conditions. This paper presents a methodology to measure vulnerability at the workplace relying on a definition of vulnerable workers as carrying the burden of working under the threat of adverse physical and psychosocial working conditions. Vulnerability is thus a forward-looking concept that allows the identification of workers who are the most exposed to work resource deprivations and more generally to ill-being at the workplace. Using a pseudo-panel derived from repeated cross-sectional data, second-order moments can be used to identify and estimate the variance of shocks on working conditions and, therefore, the probability of being exposed to adverse working conditions in the future. Estimates from the last editions of the European Working Conditions Survey (EWCS) provide a vulnerability measure both at the cohort level and at the aggregate one, allowing comparisons across European countries.; Conformément aux objectifs européens d’une croissance et d’un marché du travail plus inclusifs, la question de la vulnérabilité des travailleurs occupe un pan essentiel de la politique économique et sociale européenne. Ce travail s’insère ainsi dans une réflexion visant à définir et à mesurer les différentes formes de vulnérabilité qui peuvent survenir et se développer dans le travail en Europe. Nous proposons un cadre conceptuel et méthodologique où la vulnérabilité est définie comme le degré d’exposition des travailleurs à des risques cumulés sur le lieu de travail, ayant des effets néfastes pour le bien-être et la santé. À cette fin, un indicateur de conditions de travail défavorables est proposé : il agrège des facteurs relatifs aussi bien à l’environnement – qu’il soit physique ou social – qu’au contenu et à l’organisation du travail (forte intensité du travail, faible complexité, horaires atypiques). Cet indicateur synthétique est ensuite utilisé pour calculer la probabilité pour un travailleur d’être exposé à une dégradation de ses conditions de travail. C’est cette probabilité qui mesure la vulnérabilité aux conditions de travail dégradées. Notre mesure est construite à partir des données provenant des cinq dernières éditions de l’enquête européenne sur les conditions de travail (EWCS). S’appuyant sur les techniques d’estimation en pseudo-panel, nos résultats montrent de grandes disparités de la vulnérabilité des travailleurs occupés au sein des quinze pays fondateurs de l’Union européenne.

How to compute (super) hedging costs in rather general financial market models with transaction costs in discrete-time ? Despite the huge literature on this topic, most of results are characterizations of the super-hedging prices while it remains difficult to deduce numerical procedure to estimate them. We establish here a dynamic programming principle and we prove that it is possible to implement it under some conditions on the conditional supports of the price and volume processes for a large class of market models including convex costs such as order books but also non convex costs, e.g. fixed cost models.

The microcredit literature indicates that progressive lending should reduce default rates but that it may lead to over-indebtedness. In this study, we show that progressive lending may be safe over a range of loan sizes, beyond which a rational borrower would indulge in a strategic default. This range of loan sizes may be dependent on borrower characteristics (risk-taking, self-confidence, productivity, interest rates, subsistence needs) as well as the Microfinance Institution's strategy. Many crowdfunding sites are using artificial intelligence to assess borrower risk through social ratings. We are arguing that production functions of the borrowers also need to be added.

We present a model of worldwide crisis contagion based on the Google matrix analysis of the world trade network obtained from the UN Comtrade database. The fraction of bankrupted countries exhibits an \textit{on-off} phase transition governed by a bankruptcy threshold $\kappa$ related to the trade balance of the countries. For $\kappa>\kappa_c$, the contagion is circumscribed to less than 10\% of the countries, whereas, for $\kappa, Comment: Main article: 19 pages, 9 figures. Supplementary files: 7 pages, 2 figures, 4 tables, 1 video. Datasets, results, supplementary information, and high quality figures available at this http://perso.utinam.cnrs.fr/~lages/datasets/WTNcrisis/

International audience; This paper aims to analyze environmental Total Factor Productivity (TFP) change. Indeed, innovative environmental TFP measures are introduced through convex and non convex environmental production processes. Hence, the impacts of input and output quality change on environmental productivity variation are underscored. In addition, general decomposition of the new ratio- and difference-based environmental TFP measures is proposed. Finally, an empirical example is provided to illustrate these propositions.

In this paper, we consider an equally weighted bipartite matching market with transferability of the utility. We analyze the equilibrium of the market in the case of nearly full matching and in the case of nearly scarce matching. Considering a particular case of full matching with a quadratic specification and Gaussian distributions of the characteristics, we find entirely the analytical expression the optimal matching and of the individual surpluses gained by the partners from the sharing of the joint surplus at the equilibrium. We provide two ways to estimate the model.

This habilitation to direct doctoral theses (HDR) draws on four books published between 2008 et 2021. It considers the relationship between 'facts and figures' as a key philosophical issue. What is at stake is characterising the truth expressed by figures, examining the conventions used to produce them and bringing out alternative sets of conventions that point out a plurality of possible worlds. In the economic field, it differentiates liberalism and capitalism by distinguishing four strata (practices, norms, theories, and discourses). This leads to an alternative vision of the market economy, which in particular relies on new accounting standards, accounting being defined as the primary language of economy. More broadly, the prominence of economy, quantification, and technology marks the 'end of naturality' and the shift from the 'infinite universe' of classical science to a 'reflective system', of which social networks, big data or financial markets provide the archetype. This leads to the proposal of a more open model of knowledge, recognizing the place of contingency, irreversibility, and unsustainability. Conventions play an important role in the construction of knowledge and of the world. Taking this into account opens up space for the ‘decidable’, beyond the too narrow partition of the determined and the undecidable. Doing so allows to find a continuity between the fields of knowledge and existence, integrating change and intentionality, and positioning epistemology, ontology, metaphysics, and politics in a coherent set.; Cette habilitation à diriger des recherches s’appuie sur quatre ouvrages publiés entre 2008 et 2021. Le rapport entre « les faits et les chiffres » y émerge comme une question philosophique essen-tielle. Caractériser le type de vérité qu’énoncent les chiffres, examiner les conventions utilisées pour les produire et faire émerger des jeux de conventions alternatifs désignant une pluralité de mondes possibles est un enjeu majeur de ces recherches. Dans le champ économique, elles diffé-rencient libéralisme et capitalisme en distinguant quatre strates (pratiques, normes, théories et discours), ouvrant vers une vision alternative de l’économie de marché, qui repose en particulier sur de nouvelles normes comptables, la comptabilité étant analysée comme le langage premier de l’économie. Plus largement, la place prise par l’économie, la quantification et la technique est caractérisée comme marquant « la fin de la naturalité » et le passage de l’« univers infini » de la science classique à « un système réfléchi », dont les réseaux sociaux, le big data ou des marchés financiers fournissent l’archétype. Ce constat débouche sur la proposition d’un modèle de savoir plus ouvert, reconnaissant la place du contingent, de l’irréversible et du non durable. Et la mise en avant du rôle joué par les conventions dans la construction du savoir et du monde désigne un espace pour le décidable, par-delà la partition trop étroite du déterminé et de l’indécidable. Il s’agit, ce faisant, de trouver une continuité entre les champs du savoir et de l’existence, intégrant le changement et l’intentionnalité et positionnant épistémologie, ontologie, métaphysique et politique dans un ensemble cohérent.

We present some mathematical tools widely used in courses taught in (under)graduate programs in economics. We hope that readers can learn how to apply mathematical results in economics and how to prove them. We focus on two topics: finite-dimensional convex optimization and discrete-time dynamical systems. We also present several applications in economics.

International audience; In this paper, we propose a new definition of sustainability that includes dynamics and equity. We propose a theoretical framework that allows finding a fair and sustainable strategy for all stakeholders. More precisely, the framework allows calculating a strategy which ensures that in the long run the interests of all the stakeholders are reconciled. In order to calculate a such a strategy, we model stakeholders and actors as dynamical systems in state-space form. Furthermore, we use robust control and linear matrix inequalities to calculate the desired strategy. We use several simulation scenarios to show the effectiveness of our proposed framework. Response to Reviewers: For a detailed response to reviewer's comments please see the pdf file containing the revised manuscript and our response to reviewers attached to the revised version of our manuscript

We study how overlapping ownership affects investments in a preemption race with market uncertainty. Internalization of rival payoffs delays follower entry if product market effects are moderate, implying longer incumbency which intensifies the race to lead. Preemptive and follower investment thresholds increase with volatility as in standard real option models but firm value can decrease, and greater volatility makes internalization more profitable. From a welfare perspective there is a tradeoff between a dynamic benefit and a static cost of overlapping ownership. Whereas it is socially optimal not to have any overlapping ownership in some markets, at low volatility levels we find firms have an insufficient incentive to internalize.

This thesis deals with various issues related to the quantitative management of financial risks. In the first part, we are interested in the models of default time in credit risk within the framework of the theory of enlargement of filtration. We propose models where the default time can coincide with some economic shock times. Our initial focus is the model of Jiao and Li (2018) in sovereign risk, where the default time coincides with predictable shock times. We extend this model in cases where shocks are not predictable by studying the characteristics of the default time. Second, we present the generalized Cox model which is an extension of the one of Lando (see Lando, 1998). We offer a wide range of examples for boiling our construction. The second part deals with the construction of volatility surfaces of financial assets under the condition of no-arbitrage opportunity using kriging methodologies (also called Gaussian process regression). These surfaces allow to estimate from the price of liquid options the value of financial products whose characteristics are non-standard and whose price is not observed on the market. The construction of such surfaces is an important step in some risk management processes. It also allows to evaluate non-liquid assets. Our approach is to learn the prices of European options through kriging while respecting the no-arbitrage conditions. These conditions are characterized by shape constraints on prices, namely monotonicity in the direction of maturities and convexity in the direction of strikes. Since these constraints correspond to a finite number of linear inequalities, we adopt a kriging technique under the constraints of linear inequalities. For this, we use the method developped by Maatouk and Bay (2016) which is based on the finite-dimensional approximation of the Gaussian process. The Monte Carlo Hamiltonien algorithm developed by Pakman and Paninski (2014) will be used to simulate the Gaussian coefficients. We propose a method for computing the Maximum a Posteriori (MAP) of the Gaussian process. We compare our method with those of constrained neural networks and SSVI.; Cette thèse traite différentes questions liées à la gestion quantitative des risques financiers. Nous nous intéressons, dans une première partie, aux modèles de temps de défaut en risque de crédit dans le cadre de la théorie de grossissement de filtrations. Nous proposons des modèles où le temps de défaut peut coïncider avec des instants de chocs économiques. Nous mettons l’accent, dans un premier temps, sur le modèle de Jiao et Li (2018) en risque souverain où le temps de dèfaut coïncide avec des temps de chocs prévisibles. Nous étendons ce modèle dans le cas où les chocs ne sont pas prévisibles en étudiant les caractéristiques du temps de défaut. Dans un second temps, nous présentons le modèle de Cox généralisé qui est une extention de celui de Lando (voir Lando, 1998). Nous proposons une large gamme d’exemples pour ullistrer notre construction. La seconde partie porte sur la construction de surfaces de volatilités des actifs financiers sous la condition d’absence d’opportunité d’arbitrage (AOA) en utilisant les méthodologies de krigeage (où la regression par processus Gaussien). Ces surfaces permettent par exemple d’estimer à partir du prix d’options liquides, la valeur des produits financiers dont les caractéristiques sont non-standard et dont le prix n’est pas observé sur le marché. La construction de telles surfaces est une étape importante dans certains processus de gestion des risques. Elle permet également de tarifer des actifs non-liquides. Notre approche consiste á mettre en œuvre l’apprentissage du krigeage sur les prix d’options européennes en respectant les conditions de non-arbitrage. Ces conditions sont caractérisées par des contraintes de forme sur les prix, à savoir la monotonicité dans la direction des maturités et la convexité dans la direction des strikes. Etant donné que ces contraintes correspondent à un nombre fini d’inégalités linéaires, nous adoptons une technique de krigeage sous contraintes d’inégalités linéaires. Nous utilisons, pour cela, la méthode d’eveloppée par Maatouk et Bay (2016) qui est basée sur l’approximation fini-dimensionnelle du processus Gaussien. L’algorithme de Monte Carlo Hamiltonien de Pakman et Paninski (2014) sera utilisé pour simuler les coefficients Gaussiens. Nous proposons une méthode de calcul du Maximum a Posteriori (MAP) du processus Gaussien. Nous comparons notre méthode avec celles des réseaux de neuronne contraints et des SSVI.

With the lowering of the usury thresholds for bank loans on April 1, 2021, the Annual Percentage Rate (APR) is back in the spotlight. This rate must be specified for any credit to individuals and must be calculated according to the methods provided for by law in the Consumer Code. By its character of meter-standard of the real cost of a credit, the global rate allows to compare the offers of loan and to verify that the legal maximum is not exceeded. After half a century of legal changes, two rate indicators coexist, calculated according to two different mathematical methods. Has the initial objective of simplification been achieved?; Avec la baisse des seuils d’usure pour les prêts bancaires au 1er avril 2021, le Taux Annuel Effectif Global (TAEG) revient sur le devant de la scène. Mentionné obligatoirement pour tout crédit aux particuliers, ce taux doit être calculé selon les modalités prévues par la loi dans le Code de la consommation. Par son caractère de mètre-étalon du coût réel d’un crédit, le taux global permet de comparer les offres de prêt et de vérifier que le maximum légal n’est pas dépassé. Après un demi-siècle de rebonds juridiques, deux indicateurs de taux coexistent calculés selon deux méthodes mathématiques différentes. L’objectif de simplification initialement escompté a-t-il été atteint ?

Today, all companies in search of performance must be part of a dynamic of transformation and opt for new technologies and new management tools. The social management control, a recent function, is gradually being installed in Moroccan companies to meet the needs of HR management related to the measurement of its performance and the achievement of its objectives. Through an empirical study carried out on 500 companies with a response rate of 18% (90 companies) and by positioning ourselves on a positivist methodological posture, we were able to identify the best HR practices, namely HR Steering, Management of social relations and the best CGS practices, namely the Control of HR Steering, Control of Career Management, Control of the management of social relations, impacting positively and directly the social performance and indirectly the financial performance. Thus, we were able to testify to the positive relationship between social performance and financial performance, and to present the profile of the Moroccan social management controller, in addition to the social management control tools adopted by Moroccan companies., Aujourd’hui, toutes les entreprises en quête de la performance doivent s’inscrire dans une dynamique de transformation et opter pour de nouvelles technologies et de nouveaux outils de gestion. Le contrôle de gestion sociale, fonction récente, s’installe petit à petit dans les entreprises marocaines pour répondre aux besoins de la direction RH liées à la mesure de sa performance et à l’atteinte de ses objectifs. A travers une étude empirique réalisée sur 500 entreprises avec un taux de réponse de 18% (90 entreprises) et en se positionnant sur une posture méthodologique positiviste, nous avons pu dégager les meilleures pratiques RH à savoir le Pilotage RH, Gestion des relations sociales et les meilleures pratiques CGS à savoir le Contrôle du Pilotage RH, Contrôle de la gestion des carrières, Contrôle de la gestion des relations sociales, impactant positivement et directement la performance sociale et indirectement la performance financière. Ainsi, nous étions en mesure de témoigner de la relation positive entre la performance sociale et la performance financière, et de présenter le profil du contrôleur de gestion sociale Marocain, outre les outils de contrôle de gestion sociale adoptées par les entreprises marocaines.

We provide a comprehensive analysis of the two-parameter Beta distributions seen from the perspective of second-order stochastic dominance. By changing its parameters through a bijective mapping, we work with a bounded subset D instead of an unbounded plane. We show that a mean-preserving spread is equivalent to an increase of the variance, which means that higher moments are irrelevant to compare the riskiness of Beta distributions. We then derive the lattice structure induced by second-order stochastic dominance, which is feasible thanks to the topological closure of D. Finally, we consider a standard (expected-utility based) portfolio optimization problem in which its inputs are the parameters of the Beta distribution. We explicitly characterize the subset of D for which the optimal solution consists of investing 100% of the wealth in the risky asset and we provide an exhaustive numerical analysis of this optimal solution through (color-coded) graphs.

International audience; We present a model for research and development (R&D) investment in food innovations based on new plant engineering techniques (NPETs) and traditional hybridization methods. The framework combines uncertain and costly food innovation with consumers' willingness to pay (WTP) for the new food. The framework is applied with elicited WTP of French and US consumers for new improved apples. NPETs may be socially beneficial under full information and when the probability of success under NPETs is relatively high. Otherwise, the traditional hybridization is socially optimal. A probable collapse of conventional apples raises the social desirability of new apples generated by NPETs and traditional hybridization.; Nous présentons un modèle d'investissement en recherche et développement (R&D) dans le domaine alimentaire, en prenant en considération les nouvelles techniques d'ingénierie végétale (NTIV) et les méthodes d'hybridation traditionnelles. Le modèle intègre une innovation alimentaire incertaine et coûteuse, ainsi que les consentements à payer des consommateurs (CAP) pour le nouvel aliment. Ce cadre conceptuel est appliqué au cas de nouvelles pommes se conservant plus longtemps et brunissant moins vite, en prenant en compte les CAP des consommateurs français et américains pour ces nouvelles pommes. Il est montré que les NTIV peuvent être socialement bénéfiques dans un contexte d’information complète, et lorsque la probabilité de succès avec ces NTIV est relativement élevée. Sinon, l'hybridation traditionnelle est socialement optimale. Une menace importante sur la production des pommes conventionnelles augmente la désirabilité sociale de nouvelles pommes générées par les NTIV ou l'hybridation traditionnelle.

International audience; Préface à l’ouvrage de François Facchini sur les dépenses publiques en France dans une perspective historique et comparative

International audience; We perform meta-regressions on a single database containing 96 observations of simple ultimatum games and 144 observations of simple dictator games to disentangle the fairness hypothesis based on the degree of economic development of a country. According to the fairness hypothesis, o ers in the two games should not di er if they were motivated by a subject's fairness concerns. Using the di erence across countries between o ers in ultimatum and dictator games, we address the e ect of being exposed to the market mechanism on pure fairness concerns and other-regarding, expectations-driven fairness. Our results show in particular that the lower the level of economic development in a country, the less likely the rejection of the fairness hypothesis.

A principal component analysis based on the generalized Gini correlation index is proposed (Gini PCA). The Gini PCA generalizes the standard PCA based on the variance. It is shown, in the Gaussian case, that the standard PCA is equivalent to the Gini PCA. It is also proven that the dimensionality reduction based on the generalized Gini correlation matrix, that relies on city-block distances, is robust to out-liers. Monte Carlo simulations and an application on cars data (with outliers) show the robustness of the Gini PCA and provide different interpretations of the results compared with the variance PCA.

Throughout Bolivia, the degree of vulnerability amongst women and men to the impact of climate change is not equal. Indeed, vulnerability can vary due to regional and gender related differences, as well as varying levels of exposition to climatic events. Furthermore, this vulnerability may be exacerbated by increasing food insecurity due to climate change. This study uses a macro-micro model with a gender focus to assess the impact of climate change on food security and women poverty for Bolivia. We analyse a scenario in which specific regional damage occurs in the agricultural and livestock sector, as well as in the non-agricultural ones, due to adverse climatic events. The simulation reveals negative impacts on the Bolivian economy, with the agricultural sector being the most affected. Food availability is reduced, which ultimately leads to greater food insecurity and food poverty with female-headed households suffering the most. The results also reveal negative effects on employment and increased domestic burdens, especially among women, which increases their vulnerability with women in the highlands being the most affected.

International audience; In a time of high debt and sluggish economic growth, the Reinhart and Rogoff (2010) conjecture of a common 90% debt threshold for advanced economies triggered a controversial debate among economists and policy-makers. We analyse the relationship between public debt and economic growth for a sample of 20 advanced economies over the period of 1880–2010, using a regression kink model with an unknown threshold proposed by Hansen (2017). We show that the relationship between public debt and economic growth is time-varying and state-dependent. Particularly, the public debt and economic growth relationship is instable for each country in the sample across the whole period of 1880–2010, and the postwar period of 1950–2010, and subject to data and country heterogeneities. These findings reject the existence of any common threshold fitting all countries and call for more theory-based models that take into account fundamentals that vary between countries and impact debt–growth interactions.

International audience; How do countries respond to other countries when setting the level of their environmental expenditures? Using data from 1995-2017 on a sample of 28 OECD countries, we examine the nature and extent of strategic interactions in environmental expenditures among OECD countries using a spatial Durbin model including economic and political control variables and both economic and spatial weight matrices reflecting several interaction mechanisms. The results show the existence of significant positive spatial dependence in environmental spending suggesting that OECD countries consider their neighbors' behavior when making policy choices related to environmental expenditures. We also find that the most populous countries or those with high unemployment tend to spend less for environment while countries with a large urban population set higher levels of environmental expenditures. The results are robust to the inclusion of strong cross-sectional dependence under the form of common factors.

International audience; In this paper, we are interested in exploring the history of game theory in France, and particularly the way it was received and was diffused in the fifties. It will be shown that France was the most fertile soil in the whole continental Europe for a multidisciplinary welcoming to game theory. Reviewing certain aspects of the intellectual trajectory of the mathematician Guilbaud, the ethnologist Lévi-Strauss and the psychanalyst Lacan, we show how each of them, in his own way, played a key role in advancing game theory: (1) Guilbaud for his constancy in disseminating game theory (and mathematics in general) (2) Lévi-Strauss for his original interpretation of game theory that had some impact on social sciences; and (3) Lacan for using the contributions of game theory. Lacan and Lévi-Strauss were particularly convincing since they were instructed on request about the principles of game theory by Guilbaud.

In diesem Beitrag schätzen wir ein strukturelles autoregressives Modell (SVAR), um den Trend der zugrunde liegenden Inflation in der Demokratischen Republik Kongo zu analysieren, und folgen dem Identifikationsansatz von Blanchard und Quah (1989), um langfristige Restriktionen auf der Grundlage der Wirtschaftstheorie aufzuerlegen. Tatsächlich wird die Inflation im Lichte der Lehren der Monetaristen als ein rein monetäres Phänomen wahrgenommen, und die Neuausrichtung der Geldpolitik auf das Ziel der Preisstabilität entspringt der fast einhelligen Ansicht von Ökonomen und Zentralbankern, dass die Geldpolitik die Aktivität langfristig nicht beeinflusst. Daher haben mehrere Zentralbanken Preisstabilität als oberstes Ziel ihrer Geldpolitik festgelegt. Diese wichtige Rolle können die Zentralbanken jedoch nicht in vollem Umfang wahrnehmen, ohne die Kerninflation zu kontrollieren, da nur diese auf monetäre Faktoren zurückzuführen ist. Zu diesem Zweck verwenden wir kongolesische Daten zur Wachstumsrate der Aktivität und der Inflationsrate von 2002Q1 bis 2019Q4. Unsere Ergebnisse bestätigen im Großen und Ganzen die in der Literatur gefundenen und zeigen, dass der monetäre Schock in Übereinstimmung mit der Identifikationsbeschränkung fast keine Auswirkungen auf die Wirtschaftstätigkeit hat, was dazu tendiert, die Vertikalität der Phillips-Kurve zu bestätigen und die Persistenz des negativen realen Schocks erklärt die Volatilität der Inflation in der Demokratischen Republik Kongo (DRK) erheblich., In this paper, we estimate a structural autoregressive model (SVAR) to analyze the trend of underlying inflation in the Democratic Republic of Congo and follow the identification approach of Blanchard and Quah (1989) to impose long-run restrictions based on economic theory. Indeed, in the light of the teachings of monetarists, inflation is perceived as a purely monetary phenomenon, and the refocusing of monetary policy on the objective of price stability comes from the almost unanimous view of economists and central bankers that monetary policy does not affect activity in the long term. Thus, several central banks have adopted price stability as the ultimate objective of their monetary policy. This important role cannot be fully played, however, by central banks without controlling core inflation because, only this one is due to monetary factors. To this end, we use Congolese data on the growth rate of activity and the inflation rate from 2002Q1 to 2019Q4. Our results broadly confirm those generally found in the literature and show that the monetary shock has, in accordance with the identification constraint, almost no effect on economic activity, which tends to validate the verticality of the Phillips curve and the persistence of the negative real shock considerably explains the volatility of inflation in the Democratic Republic of Congo (DRC)., Dans ce papier, nous estimons un modèle autorégressif structurel (SVAR) pour analyser la tendance de l'inflation sous-jacente en République Démocratique du Congo et nous suivons la démarche d'identification de Blanchard et Quah (1989) pour imposer les restrictions de long terme en se basant sur la théorie économique. En effet, au regard des enseignements des monétaristes, l'inflation est perçue comme un phénomène purement monétaire, et le recentrage de la politique monétaire à l'objectif de stabilité des prix vient de la quasi-unanimité des économistes et banquiers centraux selon laquelle la politique monétaire n'affecte pas l'activité à long terme. De ce fait, plusieurs banques centrales ont adopté la stabilité des prix comme objectif ultime de leur politique monétaire. Cet important rôle ne peut cependant être pleinement joué que si les banques centrales peuvent maîtriser l'inflation sous-jacente, car c'est cette dernière qui est d'origine monétaire. Nous utilisons à cet effet les données congolaises sur le taux de croissance de l'activité et le taux d'inflation de 2002Q1 à 2019Q4. Nos résultats confortent globalement ceux généralement retrouvés dans la littérature et montrent que le choc monétaire n'a conformément à la contrainte d'identification, presque pas d'effet sur l'activité économique, ce qui tend à valider l'hypothèse de verticalité de la courbe de Phillips et la persistance du choc réel négatif explique considérablement la volatilité de l'inflation en République Démocratique du Congo (RDC).

We propose a novel approach in the assessment of a random risk variable $X$ by introducing magnitude-propensity risk measures $(m_X,p_X)$. This bivariate measure intends to account for the dual aspect of risk, where the magnitudes $x$ of $X$ tell how hign are the losses incurred, whereas the probabilities $P(X=x)$ reveal how often one has to expect to suffer such losses. The basic idea is to simultaneously quantify both the severity $m_X$ and the propensity $p_X$ of the real-valued risk $X$. This is to be contrasted with traditional univariate risk measures, like VaR or Expected shortfall, which typically conflate both effects. In its simplest form, $(m_X,p_X)$ is obtained by mass transportation in Wasserstein metric of the law $P^X$ of $X$ to a two-points $\{0, m_X\}$ discrete distribution with mass $p_X$ at $m_X$. The approach can also be formulated as a constrained optimal quantization problem. This allows for an informative comparison of risks on both the magnitude and propensity scales. Several examples illustrate the proposed approach.

This paper introduces a general framework to analyse green efficiency and environmental productivity. Innovative environmental efficiency measures are introduced to define green productivity indices. Equivalence conditions for the additive and multiplicative green efficiency and productivity measures are displayed. In addition, the core components of environmental productivity change are defined. New implementation process of environmental efficiency and productivity assessment on convex and non convex pollution-generating technologies is proposed.

In this paper, we define stochastic volatility operators in Hilbert space which are analogs to the widely-used SABR model [14] in finite dimensional case. We show the existence of the mild solution and some related regularity properties. Our proof is based on Leray-Schauder fixed point theorem and some priori inequalities on the stochastic operator processes we construct.

International audience; A variable behaving as a quantum in economic system is studied on the basis of quantum mechanics. The several formulas of relevant variable are derived along with this speculation. Thus a possible value for the common constant which may be understood as Planck constant in economic system is calculated. There, a concerned variable seems to exhibit a quantum behavior.Recently it has been pointed out that there might be a similarity between the rational expectation hypothesis in economics and quantum mechanics, where their observers are both in respective systems. Nevertheless, on the other hand, the principle of uncertainty in economics has not yet been discovered so far. Therefore we will study on this problem by starting to formulate the basic equations respective which correspond to quantum mechanics. Here we pursue solely a behavior of certain representative variable with which an important econophysical quantity is newly introduced, and then discuss about Planck constant in economic system.; Une variable se comportant comme un quantum dans un système économique est étudiée sur la base de la mécanique quantique. Les nombreuses formules de la variable pertinente sont dérivées avec cette spéculation. Ainsi, une valeur possible pour la constante commune qui peut être comprise comme la constante de Planck dans le système économique est calculée. Là, une variable concernée semble présenter un comportement quantique.Récemment, il a été souligné qu'il pourrait y avoir une similitude entre l'hypothèse de l'espérance rationnelle en économie et en mécanique quantique, où leurs observateurs sont tous deux dans des systèmes respectifs. Néanmoins, d'un autre côté, le principe d'incertitude en économie n'a pas encore été découvert à ce jour. C'est pourquoi nous allons étudier ce problème en commençant à formuler les équations de base respectives qui correspondent à la mécanique quantique. Ici, nous poursuivons uniquement le comportement d'une certaine variable représentative avec laquelle une quantité éconophysique importante est nouvellement introduite, puis discutons de la constante de Planck dans le système économique.

International audience; We built a database of two samples of patients surveyed within the same regions in rural China over a time interval of 18 years, and presumed varying demand heterogeneity due to income increase and people aging. We find that while the mean price and distance negative effects on patients choice were present in both time periods, their differences in heterogeneity, which were confirmed with the mixed multinomial logit (MMNL), could have crucial importance in avoiding erroneous policy making based merely on mean price and distance effects. We also find that while both the multinomial logit (MNL) and the MMNL are able to predict price and distance effects with low heterogeneity, only the MMNL appears able to detect the price effect when heterogeneity is high. These findings suggest using caution when interpreting estimation results with the MNL in cases of high heterogeneity.

This article proposes an original approach to backtest Expected Shortfall (ES) exploiting the definition of ES as a function of Value-at-Risk (VaR). Our methodology examines jointly the validity of the VaR forecasts along the tail distribution of the risk model, and encompasses the Basel Committee recommendation of verifying quantiles at risk levels 97.5%, and 99%. We introduce four easy-to-use backtests in which we regress the ex-post losses on the VaR forecasts in a multi-quantile regression model, and test the resulting parameter estimates. Monte-Carlo simulations show that our tests are powerful to detect various model misspecifications. We apply our backtests on S&P500 returns over the period 2007-2012. Our tests identify misleading ES forecasts in this period of financial turmoil. Empirical results also show that the detection abilities are higher when the evaluation procedure involves more than two quantiles, which should accordingly be taken into account in the current regulatory guidelines.

International audience

'Rich get richer' rule comforts previously often chosen actions. What is happening to the evolution of individual inclinations to choose an action when agents do interact ? Interaction tends to homogenize while each individual dynamics tends to reinforce its own position. Interacting stochastic systems of reinforced processes were recently considered in many papers, where the asymptotic behavior was proven to exhibit a.s. synchronization. We consider in this paper models where, even if interaction among agents is present, absence of synchronization may happen due to the choice of an individual non-linear reinforcement. We show how these systems can naturally be considered as models for coordination games, technological or opinion dynamics.

This paper investigates the determinants of firms investment financing constraints. Using an endogenous switching regression model on French Provence-Alpes Côte d'Azur region firms data collected between 2005-2014, we provide a novel evidence of the role of inter-enterprises payment deadlines which are days receivable outstanding and days payable outstanding, as factors determining rms investment nancing constraints. We also show that there is a non-negligible number of firms switching each year either from constrained regime to unconstrained regime or unconstrained regime to constrained one. By developing a model, we highlight the factors determining firms regime change.

National audience; Most integrated models of the covid pandemic have been developed under the assumption that the policy-sensitive reproduction number is certain. The decision to exit from the lockdown has been made in most countries without knowing the reproduction number that would prevail after the deconfinement. In this paper, I explore the role of uncertainty and learning on the optimal dynamic lockdown policy. I limit the analysis to suppression strategies where the SIR dynamics can be approximated by an exponential infection decay. In the absence of uncertainty, the optimal confinement policy is to impose a constant rate of lockdown until the suppression of the virus in the population. I show that introducing uncertainty about the reproduction number of deconfined people reduces the optimal initial rate of confinement.

International audience

The government of Tanzania is willing to improve the socio-economic environment for the farming sector to encourage farmers to produce (and sell) more products from their activities. To that end, the central government is reforming the local tax system and particularly the agricultural produce cess, which is a turnover tax on marketed agricultural products charged by local government authorities (LGAs) at a maximum of 5% of the farm-gate price. Although it constitutes a significant source of revenue for many LGAs, this tax restricts an increase in production by farmers, and thus improvement of their livelihoods. In 2017, the government reduced the maximum cess rate from 5% to 3%. However, this reduction seems insufficient according to stakeholders, and several options to further reduce the rate are currently under discussion by the government. This report provides an ex ante impact assessment of the main reform options, using a microeconomic simulation model called FSSIM-Dev (Farming System Simulator for Developing Countries). Based on positive mathematical programming, this model was applied to a representative sample of 3,134 farm households spread throughout the country, taken from the World Bank LSMS–ISA surveys. Simulation results show that reduction of the cess rate leads to greater intensification and an increase in farm income, ranging between +2% and +21% depending on options and regions. The largest positive impacts are observed in the Northern and Western highlands. As expected, large farms and farms specialized in cash crops tend to gain more from the reduction in cess. At the individual farm household level, the impact is modest: 95% of the farms will experience an income increase of less than 10%. The impact on food security and rural poverty reduction is quite limited (improvement is less than 2%). Finally, the results show that a uniform cess rate of 1% for all crops seems to be the most efficient policy option.; Ce rapport présente les résultats d'une analyse d'impact de plusieurs options de réforme de la taxe sur les produits agricoles en Tanzanie. Il s’agit d’une taxe sur le chiffre d'affaire des produits agricoles commercialisés perçue par les collectivités locales (LGA) fixée à un taux maximal de 5% du prix producteur. Bien qu'elle constitue une source de revenus importante pour de nombreuses LGA, cette taxe empêche l’augmentation de la production agricole, et donc l’amélioration des moyens de subsistance des exploitants. En 2017, le gouvernement a réduit le taux maximal de 5% à 3%. Cependant, cette réduction semble insuffisante selon les parties prenantes, et plusieurs options pour réduire davantage ce taux sont actuellement à l’étude par le gouvernement. Cette analyse est réalisée à l’aide d’un modèle microéconomique appliqué à un échantillon représentatif de 3134 ménages agricoles répartis sur l’ensemble du pays provenant des enquêtes LSMS-ISA de la Banque Mondiale. Les effets potentiels des options de réforme simulées sur l'utilisation des terres, la production, l'utilisation des intrants, le revenu agricole, les revenus des gouvernements locaux et certains indicateurs liés à la sécurité alimentaire sont présentés et discutés dans ce rapport.

This report presents the results of an impact analysis of several reform options of the agricultural produce cess in Tanzania. The produce cess is a levy charged by Local Governments Authorities (LGAs) on the value of the marketed agricultural production. This analysis is achieved using a micro-economic model applied to a representative sample of 3134 farm-households spread out over all the country coming from the World Bank-LSMS-ISA surveys. The potential effects of the simulated reform options on land use, production, input use, farm income, LGAs revenues and some food security related indicators are presented and discussed., JRC.D.4-Economics of Agriculture

International audience; En mars 1945, le psychanalyste Jacques Lacan publie un article intitulé « Le Temps Logique et l’Assertion de Certitude Anticipée. Un Nouveau Sophisme ». A sa parution, cet article passe complètement inaperçu tant son contenu tranche avec les précédents travaux de Lacan : il y traite, en effet, d’un problème de logique. Ajoutons que le manque de visibilité dont l’article a souffert est également dû à Lacan dans la mesure où, pendant près de 10 ans, il n’en fera aucune mention donnant l’impression qu’il correspond à une simple parenthèse. Il faudra attendre son Discours de Rome de 1953 et sa rupture avec la Société Psychanalytique de Paris pour qu’il y revienne et en souligne l’importance. Depuis, « Le Temps Logique » a été abondamment commenté, notamment par des psychanalystes et des philosophes. L’un des arguments généralement mis en avant pour justifier son originalité réside dans le mode de raisonnement développé par Lacan, celui-ci étant en lien avec la théorie des jeux.Toutefois, malgré la place prise par cet article en psychanalyse, il reste encore méconnu tant par ceux qui développent la théorie des jeux que de ceux qui l’appliquent. Dans notre article, nous nous sommes proposés d’analyser le mode de raisonnement adopté par Lacan dans le « Temps Logique » afin de montrer combien il a été novateur. Cela nous permet de montrer que, même si cela n’est pas encore reconnu, Lacan a parfaitement sa place dans l’histoire de la théorie des jeux.

International audience; The aim of this contribution is to establish a typology of European entrepreneurship countries with respect to variables related to entrepreneurial activity and economic development. Using a combination of multidimensional data analyses allows us to extend the concept of \'entrepreneurial regimes\' and leads to the distinction of five such entrepreneurial regimes. Moreover, in order to better characterize these classes, a wide set of illustrative variables representative of national economic development, labour market functioning, and formal and informal institutional environments, as well as variables specific to the entrepreneurial population, are considered. Finally, discriminant analyses show that the five explanatory themes considered (Innovation, Employment, Formal Institutions, Entrepreneurship and Governance) differentiate the classes, and significantly explain the diversity of entrepreneurial regimes. These findings have important implications for the implementation of public policy, in order to promote entrepreneurial activity and reduce unemployment.

International audience; Ce texte propose une critique radicale de la décomposition de Oaxaca-Blinder appliquée aux inégalités salariales. Cette méthode décompose un écart salarial entre deux groupes entre une part « expliquée » par les différences de compétences et une part « inexpliquée » appelée effets de la discrimination. On montre ici, en les passant en revue, que des critiques techniques nombreuses minent la prétention de la méthode à pouvoir chiffrer la discrimination. Le problème principal est cependant l'utilisation d'hypothèses contrefactuelles irréalistes. Le texte conclut donc qu'il faut renoncer à chiffrer la discrimination salariale par cette méthode et qu'il est sans doute préférable d'étudier la discrimination par d'autres voies.

In cooperative game theory, the concept of interaction index is an extension of the concept of value, considering interaction among players. In this paper we focus on cardinal-probabilistic interaction indices which are generalizations of the class of semivalues. We provide two types of decompositions. With the first one, a cardinal-probabilistic interaction index for a given coalition equals the difference between its external interaction index (or co-Möbius transfom) and a weighted sum of the individual impact of the remaining players on the interaction index of the considered coalition. The second decomposition, based on the notion of the "decomposer", splits an interaction index into a direct part, the decomposer, which measures the interaction in the coalition considered, and an indirect part, which indicates how all remaining players individually affect the interaction of the coalition considered. We propose alternative characterization of the cardinal-probabilistic interaction indices. We then propose an illustration with a well-known example in Multicriteria Aid for Decisions.

International audience; The impact of housing hazards on health outcomes is becoming a major issue especially given the recent and on-going reviews of energy legislation in many European countries. A large body of epidemiological literature argues that fuel poverty – a frequently debated example of a housing hazard involving low indoor temperatures – is associated with heightened health risks.By using a large scale nationally representative dataset, I seek in this article to delve into this alleged association and uncover a causal relationship between fuel poverty and self-assessed health. Coming from an economics standpoint, I used a panel approach based on an instrumental fixed-effects model which allow me to analyse causality. I used both objective and subjective fuel-poverty indicators.The results show that there is a significant causal relationship between fuel poverty and self-assessed health status. The estimated causality is exacerbated when subjective fuel-poverty indicators are used. The results also show that the negative impact of fuel poverty on health is deferred, meaning that fuel poverty takes time to manifest itself in terms of poor health.In policy terms, this study adds to the debate on investing in housing energy-efficiency schemes to reduce fuel poverty and thereby improve health outcomes. It also lends support to the argument according to which improving housing conditions to curb fuel poverty is a lever for reducing pubic expenditures on health care.

The interest of this paper is to show the effect of the action of the public power over the management of public expenditure on education. Our empirical attempt tries to clarify the direct and indirect effects of the efficiency of the government on the development of public spending for the education sector during the 1984-2018 periods in in the MENA region while using the model of simultaneous equations., L'intérêt de cet article est de montrer l'effet de l'action du pouvoir public sur la gestion des dépenses publiques d'éducation. Notre tentative empirique tente de clarifier les effets directs et indirects de l'efficacité du gouvernement sur le développement des dépenses publiques pour le secteur de l'éducation au cours des périodes 1984-2018 dans la région MENA tout en utilisant le modèle d'équations simultanées.

La capacite de mobilite quotidienne des jeunes, en transport individuel ou collectif, est un facteur determinant de leurs chances d’insertion professionnelle, en particulier pour les jeunes decrocheurs qui ont quitte le systeme scolaire sans acceder a une formation ou a un emploi, et pour qui la faible capacite de deplacement est un obstacle avere a l’insertion professionnelle. Dans ces conditions, comment ameliorer la mobilite de ces jeunes decrocheurs ? Dans cet article, nous presentons les resultats d’une evaluation d’impact par experience controlee de seize dispositifs innovants cibles sur ce public particulier. Portes par des associations locales ou nationales, ces dispositifs ont des contenus varies : diagnostic en matiere de mobilite, formation a la mobilite dans le cadre d’ateliers, apprentissage de modes de transport alternatifs, mise a disposition de deux-roues, aides financieres et accompagnement pour le passage du permis de conduire et pour l’acquisition d’un vehicule. La base de donnees experimentale couvre 275 jeunes suivis entre aout 2015 et decembre 2016. L’evaluation montre qu’une aide a la mobilite ameliore les chances d’acces a une formation et a un emploi. Toutefois, l’intensite des actions joue un role important. A trop faible dose, les aides a la mobilite peuvent meme avoir un effet contre-productif sur l’insertion des jeunes. Pour qu’elles soient efficaces, ces aides gagnent a etre intensives. Codes JEL : C93, J16, J61, J71

International audience; Cet article se propose de vérifier l’effet de la politique publique de mise à niveau sur l’engagement des entreprises dans l’innovation. L’étude empirique, menée sur un échantillon d’entreprises industrielles algériennes, a permis de mettre en évidence un lien positif et significatif entre l’application de la politique de mise à niveau et l’innovation de produit dans les entreprises ayant participé à ce programme, par rapport à celles qui ne l’ont pas appliqué. En outre, l’amélioration des compétences des ressources humaines, l’utilisation des NTIC et le respect des critères de performance expliquent de manière significative les différences d’engagement dans l’activité d’innovation. Quant aux déterminants traditionnels, dépenses de R&D et taille de l’entreprise, ils ne constituent pas des facteurs influençant significativement l’innovation.