nep-gth New Economics Papers
on Game Theory
Issue of 2008‒12‒21
five papers chosen by
Laszlo A. Koczy
Budapest Tech and Maastricht University

  1. A Short Proof of Reny's Existence Theorem for Payoff Secure Games By Pavlo Prokopovych
  2. Optimization incentive and relative riskiness in experimental coordination games By Dimitri Dubois; Marc Willinger; Phu Nguyen-Van
  3. Learning in experimental 2×2 games By Sebastian J. Goerg; Thorsten Chmura; Reinhard Selten
  4. Inspection games with long-run inspectors By Luciano Andreozzi
  5. Une forme minimale de coopération By Paternotte, Cédric

  1. By: Pavlo Prokopovych (Kyiv School of Economics and Kyiv Economics Institute)
    Abstract: A short proof of Reny (1999)'s equilibrium existence theorem for payoff secure games is provided. At the heart of the proof lies the concept of a multivalued mapping with the local intersection property. By means of the Fan-Browder collective fixed-point theorem, we show an approximate equilibrium existence theorem which covers a number of known games. Reny's theorem follows from it straightforwardly.
    Keywords: Discontinuous game, payoff security, transfer lower semicontinuity, approximate Nash equilibrium, Reny's theorem
    JEL: C72 C73
    Date: 2008–12
  2. By: Dimitri Dubois (LAMETA (UMR CNRS 5474), Université Montpellier 1, avenue de la mer, site Richter, C.S. 79606, 34960 Montpellier cédex 2, France.); Marc Willinger (LAMETA (UMR CNRS 5474), Université Montpellier 1, avenue de la mer, site Richter, C.S. 79606, 34960 Montpellier cédex 2, France.); Phu Nguyen-Van (THEMA-CNRS, Université de Cergy-Pontoise, 33 Boulevard du Port, F-95011 Cergy-Pontoise Cedex, France.)
    Abstract: We compare the experimental results of three stag-hunt games. In contrast to Battalio et al. (2001), our design keeps the riskiness ratio of the payoff-dominant and the risk-dominant strategies at a constant level as the optimisation premium is increased. We define the riskiness ratio as the relative payoff range of the two strategies. We find that decreasing the riskiness ratio while keeping the optimization premium constant increases sharply the frequency of the risk-dominant strategy. On the other hand an increase of the optimization premium with a constant riskiness ratio has no effect on the choice frequencies. Finally, we confirm the dynamic properties found by Battalio et al. that increasing the optimization premium favours best-response and sensitivity to the history of play.
    Keywords: Coordination game; Game theory; Experimental economics.
    JEL: C72 C92 D81
    Date: 2008–11
  3. By: Sebastian J. Goerg; Thorsten Chmura; Reinhard Selten
    Abstract: In this paper we introduce four new learning models: impulse balance learning, impulse matching learning, action-sampling learning, and payoff-sampling learning. With this models and together with the models of self- tuning EWA learning and reinforcement learning, we conduct simulations over 12 different 2×2 games and compare the results with experimental data obtained by Selten & Chmura (2008). Our results are two-fold: While the simulations, especially those with action-sampling learning and impulse matching learning successfully replicate the experimental data on the aggregate, they fail in describing the individual behavior. A simple inertia rule beats the learning models in describing individuals behavior.
    Keywords: Learning, Action-sampling, Payo?-sampling, Impulse balance, Impulse matching, Reinforcement, self-tuning EWA, 2×2 games, Experimental data
    JEL: C72 C91 C92
    Date: 2008–12
  4. By: Luciano Andreozzi
    Abstract: A single, long-run policeman faces a large population of myopic would- be criminals. This paper shows that this interaction has counterintuitive comparative static properties. A forward-looking inspector might tolerate more law violations than a short-sighted one.
    Date: 2008
  5. By: Paternotte, Cédric
    Abstract: Dans cet article, l'auteur décrit et caractérise une forme minimale de coopération, correspondant aux actions de masse impliquant un grand nombre d'agents, telles des manifestations. Il en détaille les aspects intentionnel, épistémique,stratégique et téléologique, qui résultent pour la plupart d'un aaffaiblissement spécifique que de concepts classiques. Parallèlement, l'auteur souligne le rôle crucial de concepts issus de la théorie des jeux pour la définition d'une action conjointe, minimale ou non. En fin, il soutient que la question de la rationalité d'une telle action coopérative minimale est essentielle à sa définition, alors que les analyses habituelles la considèrent au mieux comme une caractéristique possible ou souhaitable.
    Keywords: Coopération; action collective; intention de groupe; objectif collectif; équilibre; rationalité
    JEL: C71
    Date: 2008–07–01

This nep-gth issue is ©2008 by Laszlo A. Koczy. It is provided as is without any express or implied warranty. It may be freely redistributed in whole or in part for any purpose. If distributed in part, please include this notice.
General information on the NEP project can be found at For comments please write to the director of NEP, Marco Novarese at <>. Put “NEP” in the subject, otherwise your mail may be rejected.
NEP’s infrastructure is sponsored by the School of Economics and Finance of Massey University in New Zealand.