Indirect taxation is today more than third of fiscal receipts in most developed countries. In the European Union, early on, it was apparent that the implementation of the single market should lead to harmonisation of the tax rules of the Member States to facilitate the process of economic integration. The European Commission has implemented a transitional regime, binding on the number of rates and the composition of the bases, but leaving the choice of the level of rates to States. The transitional system allows countries to practice different rates and maintains the destination principle (in which transactions are taxed in the country where the purchaser resides). Eventually, the European Commission provides for establishing a "definitive" VAT system, harmonized, and in which the principle of origin would prevail, i.e. transactions are taxed in the country where resides the seller. Therefore, most of the changes in indirect taxation (VAT and excise duties) are often decided at national level to address macroeconomic and budgetary concerns, and do not follow harmonization concern. The purpose of this project is twofold. First, in the light of the theory of optimal taxation, we intent to analyze how, in the context of economic integration, Member States may want to design the composition of the base for indirect taxation and to set the level of the tax rates. Then, we also want to revisit the tax impact of indirect tax changes. Here, two aspects will receive our attention: (1) the difference in the incidence of the tax depending on whether it is ad valorem or specific; (2) in an open economy, how exporters of one country react to a VAT hike in a destination country. We also analyze the effect of VAT shocks on trade between the member states.

Une fois ces hypothèse relâchées, s’ouvre alors un nouveau domaine d’investigation très riche et les directions de recherche sont nombreuses. Parmi d’autres se posent les questions suivantes : Comment se forment les anticipations des investisseurs ? Comment évoluent ces anticipations ? Quel est l’impact des caractéristiques individuelles sur les décisions financières individuelles (choix de portefeuille, demande d’assurance) ? Comment peut-on agréger ces caractéristiques individuelles ? Quel est l’impact de l’hétérogénéité des caractéristiques individuelles sur l’équilibre ? Quels agents sont favorisés et quels agents sont éliminés dans un contexte hétérogène ? Citons, sans être exhaustif, quelques champs d’investigation illustrant le caractère interdisciplinaire du sujet et relevant de l’économie financière, de la finance comportementale, de la finance expérimentale, de la théorie de la décision, de la statistique, de la microéconomie de l'assurance, de la théorie des contrats, de la théorie des jeux… - nouveaux modèles de comportements, de partage et de mesures des risques notamment dans un contexte multi-dimensionnel - analyse des formations des croyances et des interactions entre agents (mimétisme, apprentissage,...) - agrégation des croyances et plus généralement des caractéristiques individuelles dans des économies d’échange et/ou avec production En aval, notre analyse devrait permettre d’éclairer des questions pratiques telles que : - comment l’intégration verticale peut constituer, pour une entreprise, une alternative au marché pour la gestion des risques ? - comment les fonds d’entreprise intègrent dans leur gestion des risques les contraintes liées à la tierce partie (en plus de l’épargnant et du fonds lui-même) que constitue l’entreprise à laquelle ils sont adossés ? - quel est l’impact de la présence d’initiés sur la distribution des risques entre agents ? - quels sont les déterminants de l’épargne de précaution des ménages tant d’un point de vue théorique qu’empirique dans un cadre étendu de risques multi-dimensionnels ? - quel est l’impact de l’hétérogénéité des niveaux d’aversion au risque individuels sur l’arbitrage entre stockage sur le marché physique et mécanismes de partage des risques sur les marchés dérivés de matières premières ? - quel est l’impact des contraintes induites par les mesures de risque utilisées par les investisseurs institutionnels sur la composition de leur portefeuille ? - quel est l’impact des contraintes induites par l’usage d’algorithmes de trading sur les caractéristiques de l’équilibre ? - quelles politiques de précaution face à des risques de long terme comme le risque climatique ? Plus généralement, l’objectif de notre projet est d’étudier le processus de prise de décision dans un environnement financier tant au niveau individuel (décision d’assurance, investissement, épargne,…) qu’au niveau collectif (évaluation collective des risques, règles prudentielles, partage des risques, prime de risque,…) dans des contextes très variés faisant appel à des techniques mathématiques et économiques maîtrisées par l’équipe du projet.

The cutoff phenomenon is an abrupt transition from out of equilibrium to equilibrium undergone by certain Markov processes in the limit where the size of the state space tends to infinity: instead of decaying gradually over time, their distance to equilibrium remains close to the maximal value for a while and suddenly drops to zero as the time parameter reaches a critical threshold known as the mixing time. Discovered four decades ago in the context of card shuffling, this dynamical phase transition has since then been observed in a variety of situations, from random walks on random graphs to high-temperature spin glasses. It is now believed to be universal among fast-mixing high-dimensional systems. Yet, the current proofs are case-specific and rely on explicit computations which (i) can only be carried out in oversimplified models and (ii) do not bring any conceptual insight as to why such a sharp transition occurs. Our ambition here is to identify the general conditions that trigger the cutoff phenomenon. This is one of the biggest challenges in the quantitative analysis of finite Markov chains. We believe that the key is to harness a new information-theoretic statistics called varentropy, whose relevance was recently uncovered by the PI but whose systematic estimation remains entirely to be developed. Specifically, we propose to elaborate a robust set of analytic and geometric tools to bound varentropy and control its evolution under any Markov semi-group, much like log-Sobolev inequalities do for entropy. From this, we intend to derive sharp and easily verifiable criteria allowing us to predict cutoff without having to compute mixing times. If successful, our approach will not only provide a unified explanation for all known instances of the phenomenon, but also confirm its long-predicted occurrence in a number of models of fundamental importance. Emblematic applications include random walks on expanders, interacting particle systems, and MCMC algorithms.

Technologically-driven innovation in finance (FinTech) is poised to streamline trading, reduce costs, and disrupt the existing financial architecture. I propose a research program to study the impact of FinTech on the financial system and to recommend market design solutions that optimize the implementation of FinTech products and services. The proposal has two main axes. First, from a pre-trade perspective, high-frequency discrete batch auctions are suggested as an alternative to continuous-time trading. Second, from a post-trade perspective, Blockchain technology implementation in clearing and settlement is expected to allow the instantaneuous transfer of assets and reduce trading costs. We employ a wide range of scientific methodologies. First, we build several game-theoretical models of financial markets to study the optimal design of batch auctions and of blockchain settlement. Second, we empirically test the impact of Blockchain settlement on financial markets through a series of event studies on the Australia Stock Exchange, Moscow Stock Exchange, and the Swiss-based FOREX platform Lykke. Third, we build a comprehensive laboratory experiment at Université Paris-Dauphine to study the link between trading speed and arbitrageur competition on discrete-time markets. Our research ultimately aims to offer practical solutions to relevant concerns of the market supervision authorities and exchanges alike. We address several concrete questions, such as: Should trading platforms abandon continuous-time trading in favor of discrete-time trading? Should exchanges embrace Blockchain settlement and, if so, should they opt for a public or a private ledger? How can markets and regulators employ the flexiblity of nascent technologies to improve liquidity, reduce risks, and better allocate resources in the economy?

1. Project background and scientific objectives: Apprenticeship training programs were initially designed to reduce the number of individuals leaving education without any qualification, whilst addressing the issue of workforce shortage in key economic sectors. Nowadays public agencies see apprenticeship as a way to optimize the training-job relation as well as intergenerational skill transfer. CERECA Project will develop an original contribution in two separate areas : - the study of the learning relation (master - apprentice ' trainer) - the evolution of jobs and related professional training programs. This approach will be based on the integration of three theoretical fields of management who have never been applied to this type of context : leadership, psychological contract and organizational socialization. 2. Project description and methodology : Field of research The Association Ouvrière des Compagnons du Devoir (AOCD) is an excellent field of investigation to study the learning relation and the evolution of jobs. The AOCD has 10 000 members, representing 25 different jobs. Often associated with the famous Tour de France des Compagnons, the AOCD offers an initial two-year training course, which takes place in their block-release training centres (CFA). In 2007, there were 5 698 apprentices following an initial training course in one of the eleven AOCD Training Center (among which 3 098 were in 1st year and 2 600 in 2d year). In the last ten years, the number of apprentices has increased around 64 %, confirming the success of this specific training course. The government, who wishes to increase the number of apprentices up to 500 000 in 2009, is often quoting the AOCD as a model who could develop the attractiveness of block-release training. Despite this success, the AOCD is confronted to a double challenge : 1/ instability in the number of « journeymen » (touring France after their apprenticeship) : as it is seeking to maintain the number of journeymen, the AOCD wants to understand why many of the initial apprentices do not achieve the traditional Tour de France after their apprenticeship. 2/ The AOCD also wants to measure the modifications at work on dominant representations of professional activities (decreasing interest and depreciation of manual jobs, for instance), in order to adapt their training courses. These two challenges are the starting point of CERECA Project. Methodology : Our approach is based on the complementary use of both quantitative and qualitative methodologies. It also relies on the association of transversal data gathering and a longitudinal approach. In order to be successful, our research project will focus on two complementary approaches : - a longitudinal quantitative investigation, whose main objective will be to study the tripartite training relationship (master ' apprentice ' trainer). This study ' composed of 5 separate questionaires ' will deal with 3 000 apprentices, individually followed during two years. The size of this sample is quite important compared to what is usually performed in management studies. Furthermore, 200 trainers and masters will also be questioned. - A quantitative investigation on the construction of professional identities will be carried out in the various CFA by questioning individuals involved in the elaboration of training offers inside the AOCD. 3. Expected results. There are three types of expected results : - Scientific publications at the highest international level thanks to the amount of qualitative and quantitative data collected, along with the quality of the field investigation. The objective is to publish a dozen articles with communication in national and international colloques. The main topics of these publications and communications will be organizational involvement, organization socialization, professional identities, organizational justice, leadership' - Diffusion of results to institutional actors involved in the development of apprenticeship training programmes and dissemination in professional reviews. - Construction of tools dealing with job identities, integration/orientation of apprentices (Job Realistic Preview and orientation programmes for new employees) and testing within the AOCD.