Search

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. more...

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. more...

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. more...

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 more...

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. more...

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. more...

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... more...

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. more...

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. more...

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. more...

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. more...

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... more...

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. more...

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. more...

L’intelligence territoriale est un concept nomade, une notion au contenu et aux contours encore fluctuants. Cet article se propose d’eclaircir quelques zones d’ombres en partant d’une comparaison avec une notion voisine et beneficiant d’une popularite plus grande, l’intelligence economique. Cette etude d’essence comparative montre comment deux approches divergentes de l’intelligence territoriale coexistent, chacune reposant sur une conception distincte du territoire et du developpement. more...

International audience; Trade integration and the increasing mobility of firms have raised the need for international coordination in corporate tax. In this paper, we study the ability of fiscal equalization to avoid the misallocation of capital across asymmetric countries arising from tax competition. Such a reform respects the principle according to which the tax decision is entirely left up to the nation and links nations engaged in strategic tax policy by transfers. We use a model of trade and location where firms produce under imperfect competition. Our analysis suggests that falling trade costs increase the distortion created by tax competition in the international allocation of production. However, we show that fiscal equalization based on differences in tax revenues or tax base can implement a more efficient tax wedge and spatial allocation of the tax base more...

http://www.springerlink.com/content/p1185018r6542206/fulltext.pdf; International audience; The paper examines the determinants of the creation of high tech SMEs at a regional level. Relations between the scientific and technical profile of a region, the size of the local market for biotech products and services, and economic development are explored in the French biotech industry during the 1990's. Empirical analysis shows that a high level of scientific activity within a region is necessary to sustain a continuous flow of new business creation. The likelihood of firm creation depends on scientific and technological organizational factors like cooperation between academic and private organizations. Regional policies can have positive impact on firm creation, especially by promoting diversity and excellence in science. However, contrasting with the U.S. results, the size of the local market for biotech products and services matters in the industry development more...

Cet article considère des situations de décision récurrentes. Nous présentons des règles de comportements adaptatifs ne mobilisant aucune croyance sur les comportements des autres agents. Deux grandes classes de modèles sont examinées. Premièrement, nous étudions des règles comportementales incorporant uniquement des informations personnelles. Les choix de chaque agent sont basés sur les paiements propres reçus dans le passé. De plus, certains modèles intègrent un seuil d’aspiration : l’évaluation des actions s’effectue par une comparaison entre les paiements reçus et le seuil d’aspiration. Deuxièmement, nous explorons des règles faisant intervenir des informations concernant les autres agents. Les décisions individuelles reposent alors sur un principe d’imitation. Plusieurs variantes de cette règle sont présentées et évaluées. In this paper, we consider situations where agents face repeatedly the same decision problem. We focus on adaptive rules without beliefs. We distinguish between two kinds of models. Firstly, we study adaptive rules that are only based on private information. Decisions are made on the basis of past payoffs. Moreover, some of these models incorporate an aspiration level : the agent compares the payoff which he receives to this aspiration level. Secondly, we present adaptive rules that take into account information about other agents. Each agent observes the actions of others and makes a decision via imitation. Various imitations rules are investigated and discussed.Adaptation, renforcement, seuil d’aspiration, imitation. more...

Using a linked employer-employee panel, we seek to identify corporate practices. We focus on the dissemination of knowledge in the firm. By formulating a precise definition of the firm-specific effect, we link it to the concept of wage efficiency. Human-capital externalities are therefore analyzed at a microeconomic level. We elaborate a stochastic parametric wage-frontier model (Battese and Coelli , 1995). A firm is efficient if it maximizes human-capital transmission. This procedure allows a simultaneous estimate of the wage frontier and the determinants of efficiency. The results show the role of both intra-and inter-organizational characteristics in determining wage efficiency., En utilisant un panel apparié employé-employeur, nous tentons de dégager des pratiques d’entreprise. Nous nous intéressons particulièrement à la diffusion des connaissances au sein de l’entreprise, en donnant un sens précis à l’effet spécifique d’entreprise, nous le lions au concept d’efficience salariale. Les externalités de capital humain sont donc analysées ici à un niveau microéconomique. Nous développons un modèle de frontière salariale paramétrique stochastique (Battese et Coelli , 1995) ; une entreprise est dite efficiente si elle parvient à développer au mieux la transmission de capital humain. Cette procédure permet d’estimer simultanément la frontière salariale et les déterminants de l’efficience. Les résultats montrent le rôle des caractéristiques intra-mais aussi inter-organisationnelles dans la détermination de l’efficience salariale ., Ris Catherine, Joumady Othman. Diffusion du capital humain et efficience salariale. Une application sur données appariées employé-employeur. In: Économie & prévision, n°169-171, 2005-3-5. pp. 127-137. more...

Van Damme and Weibull (1998, 2002) model the noise in games as endogenously determined tremble probabilities, by assuming that with some effort players can control the probability of implementing the intended strategy. Following their methodology, we derive logit-like adjustment rules for games played on quasi-symmetric weighted graphs and explore the properties of the ensuing Markov chain. more...

We consider a 2×2 coordination game where each agent interacts with his neighbors on a ring. Ellison (1993, Econometrica 61, 1047–1071) shows that the discrete dynamical system generated by the myopic best-reply rule converges to a Nash equilibrium or to a two-period limit cycle. Following Young (1993, Econometrica 61, 57–84), we consider a best-reply process with a sampling procedure. Particularly, we introduce a spatial sampling procedure: each agent observes a sample of information in his neighborhood and plays a best reply to it. We show that if the size of the sample of information is not too large, the best-reply process converges almost surely to a Nash equilibrium. If in addition agents experiment with small probabilities, we show that, in most cases, the risk-dominant equilibrium prevails in the long run. Furthermore, it turns out that the convergence is faster than in Ellison. more...

We consider best response dynamics with endogenous noise based on a finite game in strategic form. A player can reduce the noise level by expending an extra effort and incurring some disutility or control costs. We specify control costs that result in logit adjustment rules. The stochastically stable states of the dynamic process are partial Nash configurations, that is, states where at least one player plays a best response against the others. If the game has a potential, then the stochastically stable states coincide with the Nash equilibria on which the potential is maximized. more...