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We study farsighted coalitional stability in the context of TU-games. Chwe (1994, p.318) notes that, in this context, it is difficult to prove nonemptiness of the largest consistent. We show that every TU-game has a nonempty largest consistent set. Moreover, the proof of this result allows to conclude that each TU-game has a farsighted stable set. We go further by providing a characterization of the collection of farsighted stable sets in TU-games. We also show that the farsighted core of a TU-game is empty or equal to the set of imputations of the game. Next, we study the relationships between the core and the largest consistent set in superadditive TU-games and in clan games. In the last section, we explore the stability of the Shapley value in superadditive TU-games. We show that the Shapley value is always a stable imputation. More precisely, if the Shapley value does not belong to the core, then it constitutes a farsighted stable set. We provide a necessary and sufficient condition for a superadditive TU-game to have the Shapley value in the largest consistent set.

In this paper we consider cooperative graph games being TU-games in which players cooperate if they are connected in the communication graph. We focus our attention to the average tree solutions introduced by Herings, van der Laan and Talman [6] and Herings, van der Laan, Talman and Yang [7]. Each average tree solution is defined with re- spect to a set, say T , of admissible rooted spanning trees. Each average tree solution is characterized by efficiency, linearity and an axiom of T - hierarchy on the class of all graph games with a fixed communication graph. We also establish that the set of admissible rooted spanning trees introduced by Herings, van der Laan, Talman and Yang [7] is the largest set of rooted spanning trees such that the corresponding aver- age tree solution is a Harsanyi solution. One the other hand, we show that this set of rooted spanning trees cannot be constructed by a dis- tributed algorithm. Finally, we propose a larger set of spanning trees which coincides with the set of all rooted spanning trees in clique-free graphs and that can be computed by a distributed algorithm.

http://www.cae.gouv.fr/IMG/pdf/077.pdf

JEL Classification: F3, R30, R12, O33; Although economic historians consider technical change as being a significant factor explaining the evolution of the spatial organization of an economy, economic geography still fails to address this important issue. By developing a simple two-region general equilibrium model under monopolistic competition, we show that agglomeration is triggered by technological progress shifting production towards more skill intensive techniques.

Cet article présente quelques résultats de sélection évolutionnaire basée sur le critère de stabilité stochastique. Nous verrons que le processus de sélection favorise les états (histoires tronquées du jeu) efficaces au sens de Pareto lorsque la dynamique est impulsée par des comportements d’imitation alors qu’il favorise la sélection des états les moins risqués au sens de Morris, Rob et Shin (1995) lorsque la dynamique est impulsée par des comportements optimisateurs. Nous généraliserons ces résultats à la sélection d’ensembles d’états afin de ne pas limiter l’analyse à certaines classes de jeux finis. This paper presents results on stochastic stability in evolutionary game theory. We will see that imitation processes with bounded memory and sampling (Josephson, Matros, 2004) select Pareto outcomes whereas Fictitious Play processes with bounded memory select risk-dominant outcomes in the sense of Morris, Rob and Shin (1995). In order to consider the full class of finite games, we present generalization of these results from point-valued concepts to set-valued concepts.

Working Paper INRA-ESR Rennes N°06-02; Trade integration and the destination of public expenditures

We consider the class of (finite) spatial games. We show that the problem of determining whether there exists a Nash equilibrium in which each player has a payoff of at least k is NP-complete as a function of the number of players. When each player has two strategies and the base game is an anti-coordination game, the problem is decidable in polynomial time.

RésuméFudenberg et Kreps (1993), Young (1993), et Sela et Herreiner (1999) ont souligné l'insuffisance du critère de convergence en croyances du processus de Fictitious Play dans un cadre d'apprentissage des équilibres de Nash. En conséquence, nous choisissons d'étudier la convergence en straté gies du processus de Fictitious Play dans des jeux de coordination 2x2. Notre propos est de montrer que la convergence en stratégies de ce processus dépend de manière cruciale de la forme des croyances initiales des joueurs. Premièrement, lorsque les croyances initiales forment un profil de stratégies pures, nous établissons que la convergence en stratégies est certaine pour n'importe quelle catégorie de jeux de coordination. Deuxièmement, si les croyances initiales forment un profil de stratégies mixtes, le processus de Fictitious Play converge pour certaines catégories de jeux de coordination. Ainsi, nous caractérisons complètement les conditions assurant la convergence en stratégies.

International audience

Based on a spatial extension of an R&D investment model, this paper measures the macroeconomic impact of the French R&D policy mix on business R&D using regional data. Our measure takes into account not only the direct effect of policies but also indirect effects generated by the existence of spatial interaction between regions. Using a unique database containing information on the levels of various R&D policy instruments received by firms in French NUTS3 regions over the period 2001–2011, our estimates of a spatial Durbin model with structural breaks and fixed effects reveal the existence of a negative spatial dependence among R&D investments in regions. In this context, while a-spatial estimates would conclude that all instruments have a crowding-in effect, we show that national subsidies are the only instrument that is able to generate significant crowding-in effects. On the contrary, it seems that the design, size and spatial allocation of funds from the other instruments (tax credits, local subsidies, European subsidies) lead them to act (in the French context) as beggar-thy-neighbor policies. Fil: Montmartin, Benjamin. Université Côte d’Azur; Francia Fil: Herrera Gomez, Marcos Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Económicas, Jurídicas y Sociales. Instituto de Estudios Laborales y del Desarrollo Económico; Argentina Fil: Massard, Nadine. Université Grenoble Alpes; Francia

International audience; This article contributes to the literature on the Hayek-Keynes controversy on two points. The first contribution is to show that the question of the micro-foundations of macroeconomics is crucial to understand the Hayek-Keynes controversy. The second contribution is to reveal that Hayek's attack on the micro-foundations issue had a methodological impact on the making of the General Theory especially via the concept of marginal efficiency of capital. The paper concludes that what finally contrasts Hayek and Keynes is the kind of micro-foundations that economists should adopt to explain business cycles

Spurred on by the theory of network formation, and by the geography of innovation, traditional analyses on R&D cooperation face a deep renewal. This paper assesses the extent to which these renewals find an empirical validation. Based on the research projects submitted to the 6th Framework Program of the European Union, a binary choice model is used in order to highlight the existence of network and spatial effects alongside other microeconomic determinants of cooperation. Our findings suggest that network effects are present, so that probability of collaboration is influenced by each individual's position within the network. Social distance thus seems to matter more than geographical distance. Abstract. Los analisis tradicionales de cooperacion I+D se enfrentan a una renovacion profunda, estimulada por la teoria de formacion de redes, y la geografia de la innovacion. Este articulo evalua el alcance con que esta renovacion logra obtener una validacion empirica. Basado en proyectos de investigacion presentados al Sexto Programa Marco de la Union Europea, se emplea un modelo de eleccion binaria para poner de relieve la existencia de efectos de red y espaciales junto con otros determinantes macroeconomicos de cooperacion. Nuestros hallazgos sugieren que los efectos de red estan presentes, de modo que la probabilidad de colaboracion se ve influida por la posicion de cada individuo dentro de la red. La distancia social parece por tanto importar mas que la distancia geografica.

International audience; The theory of endogenous growth and the geography and growth synthesis both consider that local growth and spatial concentration of economic activities emanate from localised knowledge spillovers (Lucas 1988; Martin and Ottaviano 1999). Since the end of the 1980's, the spatial dimension of knowledge diffusion has been investigated from an empirical point of view, and the existence and role of local spillovers has been generally confirmed (see among others Jaffe 1989; Audretsch and Feldman 1996). The concern that now arises is to unravel the mechanisms underlying and explaining the geographical knowledge spillovers. The aim of this special issue is to present the latest new findings on such questions and to identify some new lines of research for future work. Before presenting the content of this special issue, we very briefly review the main results of the empirical literature on the geography of innovation. We also explain the context of this special issue by pointing out some of the limitations faced by this literature and, by stressing the complex dynamic and network dimensions of the observed processes of production and diffusion of knowledge.

CNRS NR; AERES NR; International audience

International audience; The purpose of this paper is to empirically investigate how regional advantages and firms characteristics influence the location of R&D. Looking at 2024 decisions of R&D lab locations in France, an extended conditional logit is implemented with spatially lagged explanatory variables to evaluate the importance of each factor and to test the spatial dimension of knowledge spillovers. The results indicate that a large market size, a large amount of ideas, and a low level of competition in the target region increases the probability of setting up R&D labs while the diffusion of knowledge across regions induces a significant spatial dependence.

IntroductionLe développement régulier de la théorie des jeux impulse nombre de travaux en économie industrielle et l’économie industrielle, en retour, soulève de nouvelles questions en théorie des jeux. Cette interdépendance croît à un point tel que le langage de l’économie industrielle est aujourd’hui difficilement dissociable de celui de la théorie des jeux. D’un côté, la fixation stratégique de variables micro-économiques (prix, localisation des activités, capacités de production, quantité...

A strategic model of network formation is developed which permits unreliable links and organizational costs. Finding a connected Nash network which guarantees a given payoff to each player proves to be an NP-hard problem. For the associated evolutionary game with asynchronous updating and logit updating rules, the stochastically stable networks are characterized.The organization of agents into networks has an important role in the communication of information within a spatial structure. One goal is to understand how such networks form and evolve over time. Our agents are endowed with some information which can be accessed by other agents forming links with them. Link formation is costly and communication not fully reliable. We model the process of network formation as a non-cooperative game, and we then focus on Nash networks. But, showing existence of a Nash network with particular properties and computing one are two different tasks. The aim of this paper is to show that computing a connected Nash network is a computationally demanding optimization problem. The question then arises what outcomes might be chosen by agents who would like to form a connected Nash network but fail to achieve their goal because of computational limitations. We propose a stochastic evolutionary model. By solving a companion global optimization problem, this model selects a subset of Nash networks referred to as the set of stochastically stable networks.

International audience; This paper estimates the effects of knowledge spillovers on patent growth rates across 335 European regions over the 1989-1999 period. We propose a dynamic model based on an innovation production function. A Bayesian approach is used to take into account area-specific innovation and spatial spillovers. The estimation of the model proceeds via Markov Chain Monte Carlo simulation. The results show significant positive and negative spatial effects on innovative activity. The model allows for a rich spatial specification, which we illustrate by incorporating transport proximity measured by transportation time between regions to augment the typical spatial proximity measure of connectivity between regions. Doing this produces more pronounced spatial spillovers that exhibit a more polarized spatial pattern than a model relying on spatial proximity alone

International audience; In the present paper, we are interested in the one-way flow model of Bala and Goyal (2000) [Bala, V., Goyal, S., 2000. A non-cooperative model of network formation, Econometrica, N. 68 (5), 1181-1229]. We generalize this model by relaxing the authors' assumption concerning the relation between the number of resources obtained by an agent and this agent's payoffs. Firstly, we show that Nash networks are line bases and strict Nash networks are minimum line bases. Secondly, we establish that efficient networks are minimum line bases.

In cooperative Cournot oligopoly games, it is known that the β-core is equal to the α-core, and both are non-empty if every individual profit function is continuous and concave (Zhao, Games Econ Behav 27:153–168, 1999b). Following Chander and Tulkens (Int J Game Theory 26:379–401, 1997), we assume that firms react to a deviating coalition by choosing individual best reply strategies. We deal with the problem of the non-emptiness of the induced core, the γ-core, by two different approaches. The first establishes that the associated Cournot oligopoly Transferable Utility (TU)-games are balanced if the inverse demand function is differentiable and every individual profit function is continuous and concave on the set of strategy profiles, which is a step forward beyond Zhao’s core existence result for this class of games. The second approach, restricted to the class of Cournot oligopoly TU-games with linear cost functions, provides a single-valued allocation rule in the γ-core called Nash Pro rata (NP)-value. This result generalizes Funaki and Yamato’s (Int J Game Theory 28:157–171, 1999) core existence result from no capacity constraint to asymmetric capacity constraints. Moreover, we provide an axiomatic characterization of this solution by means of four properties: efficiency, null firm, monotonicity, and non-cooperative fairness.

Axés initialement sur la mesure de la dimension géographique des externalités de connaissances à des niveaux spatiaux agrégés, les travaux en économie géographique de l’innovation sont progressivement amenés à se tourner vers l’analyse des mécanismes sous-jacents à la diffusion de connaissances dans l’espace (capacité d’absorption, échanges en face à face, mobilités professionnelles…). La mise en évidence de ces mécanismes justifie à son tour les perspectives de recherche orientées vers la compréhension des comportements individuels de coopération en matière d’innovation. Ces comportements fondent en effet la dynamique des réseaux d’acteurs qui caractérise aujourd’hui les phénomènes d’innovation collective et qui cumule des dimensions locales et globales. Une meilleure compréhension des déterminants de la configuration spatiale de ces réseaux apparaît aujourd’hui essentielle à une bonne appréciation des rapports innovation-espace. Cet article se donne pour objectif de retracer la logique des recherches menées dans ce domaine ces dernières décennies. Leading on from the measurement of the geographical dimension of knowledge externalities at aggregated spatial levels, the works carried out in the economic geography of innovation have gradually turned towards the analysis of the mechanisms underlying the spatial diffusion of knowledge (absorption capacity, face-to-face exchanges, professional mobility). Bringing these mechanisms to the fore has justified new researches which have been directed at understanding individual behavioural patterns in terms of cooperation for innovation. Indeed, the dynamics of the networks of actors who nowadays characterise collective innovation phenomena and combine local and global dimensions is based upon such behaviour. Thus, it would appear that a better understanding of the factors determining the spatial configuration of these networks has become necessary in order to fully grasp the relationships between innovation and space. The objective of this article is to go back over the logic of the researches carried out in this field during the last decades.

We study the impact of public good spillovers on tax competition between two imperfectly integrated countries with different levels of productivity. We show that international public good spillovers, by reducing the tax gap between countries, strengthen the agglomeration of firms in the most productive country. Then we carry on a welfare analysis. We first assume that governments are engaged in a redistributive tax policy. At the non-cooperative equilibrium, the tax level in the high- productivity country is inefficiently high while it is inefficiently low in the other country. A different conclusion emerges when tax revenues are recycled in a public good provision: taxes are inefficiently low in both countries and public good spillovers increase the global welfare. Finally, for a given amount of total tax revenues, public good provision in the high-productivity country is inefficiently high compared to its level in the low-productivity country.

We provide a generalization of the position value (Meessen 1988) that allows players to benefit from transfers of worth by investing in their communication links. The player who invests the most in a communication link obtains a compensation from the second one. We characterize this new allocation rule on the class of communication situations with cycle-free graphs by means of six axioms. The first two axioms, component efficiency and superfluous link property, are used to characterize the position value (Borm, Owen, and Tijs (1992)). Quasi-additivity is a weak version of the standard additivity axiom. Link decomposability captures the fact that the insurance system only allows compensations between players who share a link. Weak positivity states that if the communicative strength of a link is non null, its adjacent players cannot obtain a null payoff. Finally, weak power inversion reflects the compensation mechanism.

This paper deals with contractual design and vertical relationships within a franchise chain, in the field of the literature on share contracts. Within a double-sided moral hazard, the contract sharing the profit generated by the vertical decentralized structure results from the necessity to incite both the franchisee and the franchisor. This paper takes into account the five franchisor incentive mechanisms in order to study the chosen type of vertical coordination in different contexts. Using a multinational European dataset, we provide evidence that the two-sided externalities and monitoring costs have an influence on the type of vertical coordination in the network

Massard N. and Mehier C. Proximity and innovation through an ‘accessibility to knowledge’ lens, Regional Studies. The aim of this paper is to improve understanding of the spatial diffusion process of knowledge in terms of accessibility, and also to elaborate a new measurement and evaluation tools adapted to a concrete estimation of these phenomena. This approach offers ways of giving an operational content to the concept of proximity. The ‘potential functions’ used to measure geographical accessibility is enriched with the integration of the characteristics of knowledge diffusion, namely sources of externalities/knowledge, ways of transmission, and absorptive capacity. The paper especially focuses on the relational and strategic dimensions of proximity by using some developments from social networks analysis. Such an approach leads to new empirical models for estimating the determinants of accessibility to knowledge. Massard N. et Mehier C. Proximite et innovation: une approche par l'accessibilite aux con...

We build a model of trade and location with two countries which differ with respect to their level of productivity. Public expenditures are shared between a subsidy to firms reducing the labor cost and another one to households. We show that the high-productivity country pays a lower net subsidy to each firm than does the other country. Nevertheless, the high-productivity country succeeds in attracting a majority of firms and invests more public expenditures for firms and households if trade cost are high enough. Finally, the welfare analysis suggests that the non-cooperative level of net subsidy to firms can be inefficiently low in the high-productivity country under some conditions -- such as the distribution of profits and the level of trade costs -- while it is always inefficiently high in the low-productivity country.; Nous développons un modèle de commerce et de localisation comprenant deux pays différents en terme de productivité. Les dépenses publiques ont deux affectations possibles : une subvention forfaitaire aux ménages immobiles et une aide aux firmes mobiles diminuant le coût salarial qu’elles supportent. Nous montrons qu’à l’équilibre en subventions le pays à haute productivité alloue aux firmes une aide publique nette de taxe plus faible. En dépit de cette politique moins généreuse, le premier pays accueille une plus grande part de firmes de sorte que ses dépenses totales en faveur de ces dernières peuvent être plus importantes que dans le pays à faible productivité quand l’intégration commerciale est suffisamment avancée. L’analyse de bien-être suggère que l’optimum de second rang nécessite une politique plus généreuse vis-à-vis des ménages lorsque les économies sont faiblement intégrées, que l’écart de productivité est faible ou qu’une part importante des propriétaires du capital réside en dehors des deux économies.

The "Geography of Innovation" is based on the desire to give empirical foundations to the explanations behind the pronounced spatial polarisation of the innovation activities. It focuses on an attempt to measure the spatial dimension of knowledge externalities, in order to reveal their role in the organisation of research systems. The aim of this paper is to survey this empirical literature in order to highlight the main results interesting for the innovation policy. This analysis emphasises one main role of technology policy : supporting the institutions which generate knowledge and learning. These are found at various territorial levels, especially within the European Union. Here attention is drawn to the regional intervention level.

International audience; Despite the fact that up to now France has never used economic incentives to manage nitrate NPS pollution, this article reconsiders the potential of these instruments. The analysis is carried out on the basis of our European neighbours' experience —whenever possible—, or of theoretical advances and lab experiments. In particular, our analysis of several field experiments suggests that devices proposed to farmers must be the most efficient as possible, but also that they must be fair in order to mitigate social acceptability issues. However, the most ambitious devices have high costs of implementation, which can dissuade the regulator to use them. Hence, it becomes important to find means of reducing them. We tackle this question by describing two promising solutions: On the one hand, the introduction of retroactive audits, on the other hand, the use of ambient inspections.; Bien que la France ait écarté jusqu'ici l'idée de recourir à des instruments incitatifs pour réduire la pollution diffuse aux nitrates, cet article revient sur le potentiel de ces instruments tels qu'ils ont été employés par certains de nos voisins européens ou à défaut, tels qu'ils ont été conçus et testés en laboratoire. Il ressort en particulier de l'analyse de plusieurs expériences menées sur le terrain que les dispositifs doivent être les plus efficients possibles, mais aussi paraître justes aux acteurs, sans quoi se pose la question de leur acceptabilité. Pour autant, les dispositifs les plus ambitieux ont des coûts de mis en œuvre élevés qui peuvent dissuader les régulateurs. Il convient donc de trouver des moyens de les réduire, question que nous abordons ici en évoquant alors deux pistes prometteuses : l'introduction de la rétroactivité dans les contrôles d'une part et le recours à des inspections ambiantes de l'autre.

We consider a multimarket framework where a set of firms compete on two interrelated oligopolistic markets. Prior to competing in these markets, firms can spy on others in order to increase the quality of their product. We characterize the equilibrium espionage networks and networks that maximize social welfare under the most interesting scenario of diseconomies of scope. We find that in some situations firms may refrain from spying even if it is costless. Moreover, even though spying leads to increased product quality, there exist situations where it is detrimental to both consumer welfare and social welfare.

The aim of this paper is to highlight the relevance of a geographical multilevel technology policy within the European Union. At the present time the European policy of innovation is a "community" policy, in other words it involves a sharing of skills. In this paper we argue that outside the problems that this situation inherently poses, this territorial organisation may be considered as an asset. We use the central concept of technology externalities, taken in its traditional shape and in its renewals, to provide theoretical justifications for a “territorialised technology policy”, that is to say a policy of innovation designed and implemented on several territorial levels. Three levels are here taken into account : regional, national, European.

L'objectif de ce travail de recherche était de mettre en lumière les conditions de mise en œuvre et les bénéfices attendus de quatre pôles de compétitivité de la région PACA (Solutions communicantes sécurisées ; Mer, sécurité et sûreté, Développement durable ; Fruits et légumes ; Parfums, arômes, senteurs, saveurs). Le questionnement e a été décliné suivant deux axes : 1/ quelle est la capacité réelle de ces dispositifs à produire, diffuser et utiliser des ressources scientifiques et techniques ? Les pôles de compétitivité ont en charge de produire de nouvelles ressources dans des tissus productifs préexistants. Comment s'articulent ces nouvelles ressources avec celles déjà existantes ? Sont-elles susceptibles de se féconder mutuellement ? Mais dans le même temps, n'y a-t-il pas des risques de polarisation de l'activité et de ce fait, des risques d'exclusion ? 2/ quelle est la capacité réelle du nouveau dispositif à susciter et installer durablement la coopération nécessaire à la création des ressources attendues ?

L'objectif de ce travail de recherche était de mettre en lumière les conditions de mise en œuvre et les bénéfices attendus de quatre pôles de compétitivité de la région PACA (Solutions communicantes sécurisées ; Mer, sécurité et sûreté, Développement durable ; Fruits et légumes ; Parfums, arômes, senteurs, saveurs). Le questionnement e a été décliné suivant deux axes : 1/ quelle est la capacité réelle de ces dispositifs à produire, diffuser et utiliser des ressources scientifiques et techniques ? Les pôles de compétitivité ont en charge de produire de nouvelles ressources dans des tissus productifs préexistants. Comment s'articulent ces nouvelles ressources avec celles déjà existantes ? Sont-elles susceptibles de se féconder mutuellement ? Mais dans le même temps, n'y a-t-il pas des risques de polarisation de l'activité et de ce fait, des risques d'exclusion ? 2/ quelle est la capacité réelle du nouveau dispositif à susciter et installer durablement la coopération nécessaire à la création des ressources attendues ?

International audience; We investigate the computational complexity of several decision problems in a simple strategic game of network formation.We find that deciding if a player has a strategy that guarantees him a certain payoff against a given strategy profile of the other players is an NP-complete problem. Deciding if there exists a strategy profile that guarantees a certain aggregate payoff is also NP-complete. Deciding if there is a Nash equilibrium in pure strategies which guarantees a certain payoff to each player is NP-hard. The problem of deciding if a given strategy profile is a Nash equilibrium is investigated as well.

International audience; This empirical note deals with the contractual design of relationships between producers and retailers. It provides evidence on the links between the features of vertical contracts organizing franchising networks and the performances of these networks. An agency perspective is used to understand the structure of contracts. We focus on the relevance of vertical restraints by the upstream firm to prevent retailers from free-riding in the distribution networks. From six frequent contractual provisions we distinguish two types of contracts according to the degree of constraint imposed on the franchisees. Econometric estimations carried out on this basis offer evidence consistent with the hypothesis that within franchising systems, more constrained contracts for retailers encourage better performance at the network level.

In this paper, we compare two different representations of Framework Programs as affiliation network: “One-mode networks” and “Two-mode networks”. The aim of this article is to show that the choice of the representationhas an impact on the analysis of the networks and on the results of the analysis. In order to support our proposals, we present two forms of representation and different indicators used in the analysis. We study the network of the 6th Framework Program using the two forms of representation. In particular, we show that the identification of the central nodes is sensitive to the chosen representation. Furthermore, the nodes forming the core of the network vary according to the representation. These differences of results are important as they can influence innovation policies.