nep-gth New Economics Papers
on Game Theory
Issue of 2014‒07‒13
twelve papers chosen by
Laszlo A. Koczy
Hungarian Academy of Sciences and Obuda University

  1. Autonomous coalitions. By Stéphane Gonzalez; Michel Grabisch
  2. The positive core for games with precedence constraints. By Michel Grabisch; Peter Sudhölter
  3. On reduced games and the lexmax solution By Llerena Garrés, Francesc; Mauri Masdeu, Llúcia
  4. Bargaining over a common conceptual space. By Marco LiCalzi; Nadia Mâagli
  5. A Sequential Allocation Problem: The Asymptotic Distribution of Resources By Hurt, Wesley; Osório, António (António Miguel)
  6. A condition for determinacy of optimal strategies in zero-sum convex polynomial games By Arias-R., Omar Fdo.
  7. When Ignorance is Bliss* : Information Asymmetries Enhance Prosocial Behavior in Dicator Games By Winschel, Evguenia; Zahn, Philipp
  8. How Individual Preferences are Aggregated in Groups: An Experimental Study By Attila Ambrus; Ben Greiner; Parag A. Pathak
  9. Moral Hazard in Repeated Procurement of Services By Esteve González, Patrícia
  10. A Theory of Representative Behavior in the Dictator Game By Giménez Gómez, José M. (José Manuel); Osório, António (António Miguel)
  11. Dynamiken in asymmetrischen Konflikten: eine Simulationsstudie By Beckmann, Klaus; Reimer, Lennart
  12. Auction Format and Auction Sequence in Multi-Item Multi-Unit Auctions - An experimental study By Regina Betz; Ben Greiner; Sascha Schweitzer; Stefan Seifert

  1. By: Stéphane Gonzalez (Centre d'Economie de la Sorbonne - Paris School of Economics); Michel Grabisch (Centre d'Economie de la Sorbonne - Paris School of Economics)
    Abstract: We consider in this paper solutions for TU-games where it is not assumed that the grand coalition is necessarily the final state of cooperation. Partitions of the grand coalition, or balanced collections together with a system of balancing weights interpreted as a time allocation vector are considered as possible states of cooperation. The former case corresponds to the c-core, while the latter corresponds to the aspiration core or d-core, where in both case, the best configuration (called a maximising collection) is sought. We study maximising collections and characterize them with autonomous coalitions, that is, coalitions for which any solution of the d-core yields a payment for that coalition equal to its worht. In particular we show that the collection of autonomous coalitions is balanced, and that one cannot have at the same time a single possible payment (core element) and a single possible configuration. We also introduce the notion of inescapable coalitions, that is, those present in every maximising collection. We characterize the class of games for which the sets of autonomous coalitions, vital coalitions (in the sense of Shellshear and Sudhölter), and inescapable coalitions coincide, and prove that the set of games having a unique maximising coalition is dense in the set of games.
    Keywords: Cooperative game, core, balancedness, c-core, aspiration core, coalition formation, autonomous coalitions.
    JEL: C71
    Date: 2014–05
  2. By: Michel Grabisch (Centre d'Economie de la Sorbonne - Paris School of Economics); Peter Sudhölter (COHERE - University of Southern Denmark)
    Abstract: We generalize the characterizations of the positive core and the positive prekernel to TU games with precedence constraints and show that the positive core is characterized by non-emptiness (NE), boundedness (BOUND), covariance under strategic equivalence, closedness (CLOS), the reduced game property (RGP), the reconfirmation property (RCP) for suitably generalized Davis-Maschler reduced games, and the possibility of nondiscrimination. The bounded positive core, i.e., the union of all bounded faces of the positive core, is characterized similarly. Just RCP has to be replaced by a suitable weaker axiom, a weak version of CRGP (the converse RGP) has to be added, and CLOS can be deleted. For classical games the prenucleolus is the unique further solution that satisfies the axioms, but for games with precedence constraints it violates NE as well as the prekernel. The positive prekernel, however, is axiomatized by NE, anonymity, reasonableness, the weak RGP, CRGP, and weak unanimity for two-person games (WUTPG), and the bounded positive prekernel is axiomatized similarly by requiring WUTPG only for classical two-person games and adding BOUND.
    Keywords: TU games, restricted cooperation, game with precedence constraints, positive core, bounded core, positive prekernel, prenucleolus.
    JEL: C71
    Date: 2014–04
  3. By: Llerena Garrés, Francesc; Mauri Masdeu, Llúcia
    Abstract: For a family of reduced games satisfying a monotonicity property, we introduced the reduced equal split-off set, an extension of the equal split-off set (Branzei et. al, 2006), and study its relation with the core. Regardless of the reduction operation we consider, the intersection between both sets is either empty or a singleton containing the lexmax solution (Arin et al., 2008). We also provide a procedure for computing the lexmax solution for a class of games that includes games with large core (Sharkey, 1982). [JEL Classification: C71]
    Keywords: Jocs cooperatius, 51 - Matemàtiques,
    Date: 2014
  4. By: Marco LiCalzi (Università Ca' Foscari Venezia - Department of Management); Nadia Mâagli (Centre d'Economie de la Sorbonne et Università Ca'Foscari Venezia)
    Abstract: Two agents endowed with different individual conceptual spaces are engaged in a dialectic process to reach a common understanding. We model the process as a simple non-cooperative game and demonstrate three results. When the initial disagreement is focused, the bargaining process has a zero-sum structure. When the disagreement is widespread, the zero-sum structure disappears and the unique equilibrium requires a retraction of consensus: two agents who individually agree to associate a region with the same concept end up rebranding it as a different concept. Finally, we document a conversers' dilemma: such equilibrium outcome is Pareto-dominated by a cooperative solution that avoids retraction.
    Keywords: Cognitive maps, language differences, semantic bargaining, organisational codes, mental models.
    JEL: C78 D83
    Date: 2014–01
  5. By: Hurt, Wesley; Osório, António (António Miguel)
    Abstract: In this paper we consider a sequential allocation problem with n individuals. The first individual can consume any amount of some endowment leaving the remaining for the second individual, and so on. Motivated by the limitations associated with the cooperative or non-cooperative solutions we propose a new approach. We establish some axioms that should be satisfied, representativeness, impartiality, etc. The result is a unique asymptotic allocation rule. It is shown for n = 2; 3; 4; and a claim is made for general n. We show that it satisfies a set of desirable properties. Key words: Sequential allocation rule, River sharing problem, Cooperative and non-cooperative games, Dictator and ultimatum games. JEL classification: C79, D63, D74.
    Keywords: Teoria de jocs, Economia del benestar, Decisió de grup, 33 - Economia,
    Date: 2014
  6. By: Arias-R., Omar Fdo.
    Abstract: The main purpose of this paper is to prove that if there is a non-expansive map relating the sets of optimal strategies for a convex polynomial game, then there exists only one optimal strategy for solving that game. We introduce the remark that those sets are semi-algebraic. This is a natural and important property deduced from the polynomial payments. This property allows us to construct the space of strategies with an infinite number of semi-algebraic curves. We semi-algebraically decompose the set of strategies and relate them with non-expansive maps. By proving the existence of an unique fixed point in these maps, we state that the solution of zero-sum convex polynomial games is determined in the space of strategies.
    Keywords: determinacy, polynomial game, semi-algebraic set and function
    JEL: C63 C73
    Date: 2014–07–03
  7. By: Winschel, Evguenia; Zahn, Philipp
    Abstract: In most laboratory experiments concerning prosocial behavior subjects are fully informed how their decision influences the payoff of other players. Outside the laboratory, however, individuals typically have to decide without such detailed knowledge. To asses the effect of information asymmetries on prosocial behavior, we conduct a laboratory experiment with a simple non-strategic interaction. A dictator has only limited knowledge about the benefits his prosocial action generates for a recipient. We observe subjects with heterogenous social preferences. While under symmetric information only individuals with the same type of preferences transfer, under asymmetric information different types transfer at the same time. As a consequence and the main finding of our experiment, uninformed dictators behave more prosocially than informed dictators.
    Keywords: Asymmetric Information , Prosocial Behavior , Efficiency Concern , Inequality Aversion , Dictator Game
    JEL: D82 C91
    Date: 2014
  8. By: Attila Ambrus (Department of Economics, Duke University); Ben Greiner (School of Economics, Australian School of Business, the University of New South Wales); Parag A. Pathak (Department of Economics, MIT)
    Abstract: This paper experimentally investigates how individual preferences, through unrestricted deliberation, are aggregated into a group decision in two contexts: reciprocating gifts and choosing between lotteries. In both contexts, we find that median group members have a significant impact on the group decision, but the median is not the only influential group member. Non-median members closer to the median tend to have more influence than other members. By investigating the same individual’s influence in different groups, we find evidence for relative position in the group having a direct effect on influence. These results are consistent with predictions from a spatial model of dynamic bargaining determining group choices. We also find that group deliberation involves bargaining and compromise as well as persuasion: preferences tend to shift towards the choice of the individual’s previous group, especially for those with extreme individual preferences.
    Keywords: group decision-making, role of deliberation, social influence
    JEL: C72 C92 H41
    Date: 2014–06
  9. By: Esteve González, Patrícia
    Abstract: This paper analyzes repeated procurement of services as a four-stage game divided into two periods. In each period there is (1) a contest stage à la Tullock in which the principal selects an agent and (2) a service stage in which the selected agent provides a service. Since this service effort is non-verifiable, the principal faces a moral hazard problem at the service stages. This work considers how the principal should design the period-two contest to mitigate the moral hazard problem in the period-one service stage and to maximize total service and contest efforts. It is shown that the principal must take account of the agent's past service effort in the period-two contest success function. The results indicate that the optimal way to introduce this `bias' is to choose a certain degree of complementarity between past service and current contest efforts. This result shows that contests with `additive bias' (`multiplicative bias') are optimal in incentive problems when effort cost is low (high). Furthermore, it is shown that the severity of the moral hazard problem increases with the cost of service effort (compared to the cost of contest effort) and the number of agents. Finally, the results are extended to more general contest success functions. JEL classification: C72; D82 Key words: Biased contests; Moral Hazard; Repeated Game; Incentives.
    Keywords: Jocs no-cooperatius (Matemàtica), 33 - Economia,
    Date: 2014
  10. By: Giménez Gómez, José M. (José Manuel); Osório, António (António Miguel)
    Abstract: In this paper we present a model of representative behavior in the dictator game. Individuals have simultaneous and non-contradictory preferences over monetary payoffs, altruistic actions and equity concerns. We require that these behaviors must be aggregated and founded in principles of representativeness and empathy. The model results match closely the observed mean split and replicate other empirical regularities (for instance, higher stakes reduce the willingness to give). In addition, we connect representative behavior with an allocation rule built on psychological and behavioral arguments. An approach consistently neglected in this literature. Key words: Dictator Game, Behavioral Allocation Rules, Altruism, Equity Concerns, Empathy, Self-interest JEL classification: C91, D03, D63, D74.
    Keywords: Disseny d'experiments, Microeconomia, Economia del benestar, Decisió de grup, 33 - Economia,
    Date: 2014
  11. By: Beckmann, Klaus (Helmut Schmidt University, Hamburg); Reimer, Lennart (Helmut Schmidt University, Hamburg)
    Abstract: Wir illustrieren den Einsatz von Simulationstechniken zur Betrachtung komplexer Dynamiken in asymmetrischen Konfliktsituationen mit begrenzt rationalen Akteuren. Dazu wird erst ein formaler Modellrahmen entwickelt, dessen Steady state wir bestimmen. Darauf baut eine Umsetzung des Modells in SIMULINK und die Entwicklung von Entscheidungsverfahren für die Spieler auf. Anhand eines Basisszenarios diskutieren wir typische Verläufe von asymmetrischen Konflikten.
    Keywords: conflict dynamics; simulation; terrorism; media
    JEL: C72 D74
    Date: 2014–07–03
  12. By: Regina Betz (Australian School of Business, the University of New South Wales); Ben Greiner (School of Economics, Australian School of Business, the University of New South Wales); Sascha Schweitzer (University of Bayreuth); Stefan Seifert (University of Bayreuth)
    Abstract: We experimentally study the effect of auction format (sealed-bid vs. closed clock vs. open clock) and auction sequence (simultaneous vs. sequential) on bidding behaviour and auction outcomes in auctions of multiple related multi-unit items. Prominent field applications are the sale of emission permits, fishing rights, and electricity. We find that, when auctioning simultaneously, clock auctions outperform sealed-bid auctions in terms of efficiency and revenues. This advantage disappears when the items are auctioned sequentially. In addition, auctioning sequentially has positive effects on total revenues across all auction formats, resulting from fiercer competition on the item auctioned first.
    Keywords: emission permits, auction design, laboratory experiment
    JEL: C90 D44 Q53
    Date: 2014–06

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