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on Game Theory |
| By: | Sung, Shao-Chin; Dimitrov, Dinko |
| Abstract: | We investigate the computational complexity of several decision problems in hedonic coalition formation games and demonstrate that attaining stability in such games remains NP-hard even when they are additive. Precisely, we prove that when either core stability or strict core stability is under consideration, the existence problem of a stable coalition structure is NP-hard in the strong sense. Furthermore, the corresponding decision problems with respect to the existence of a Nash stable coalition structure and of an individually stable coalition structure turn out to be NP-complete in the strong sense. |
| Keywords: | additive preferences; coalition formation; computational complexity; hedonic games; NP-hard; NP-complete |
| JEL: | C63 C70 C71 |
| Date: | 2008–10–07 |
| URL: | http://d.repec.org/n?u=RePEc:lmu:muenec:6430&r=gth |
| By: | Sergiu Hart; Andreu Mas-Colell |
| Date: | 2008–10–12 |
| URL: | http://d.repec.org/n?u=RePEc:cla:levarc:122247000000002406&r=gth |
| By: | Werner Güth (Max Planck Institute of Economics, Strategic Interaction Group, Jena, Germany); M. Vittoria Levati (Max Planck Institute of Economics, Strategic Interaction Group, Jena, Germany); Matteo Ploner (Max Planck Institute of Economics, Strategic Interaction Group, Jena, Germany, and University of Trento, Italy) |
| Abstract: | The satisficing approach is generalized and applied to finite n-person games. Based on direct elicitation of aspirations, we formally define the concept of satisficing, which does not exclude (prior-free) optimality but includes it as a border case. We also review some experiments on strategic games illustrating and partly supporting our theoretical approach. |
| Keywords: | Strategic interaction, Satisficing behavior, Bounded rationality |
| JEL: | C72 C92 D01 |
| Date: | 2008–10–16 |
| URL: | http://d.repec.org/n?u=RePEc:jrp:jrpwrp:2008-078&r=gth |
| By: | Stephanie Rosenkranz; Utz Weitzel |
| Abstract: | This paper analyzes the effects of network positions and individual risk attitudes on individuals' strategic decisions in an experiment where actions are strategic substitutes. The game theoretic basis for our experiment is the model of Bramoulle and Kranton (2007). In particular, we are interested in disentangling the influence of global, local and individual factors. We study subjects' strategic investment decisions in four basic network structures. As predicted, we find that global factors, such as the regularity of the network structure, influence behavior. However, we also find evidence that individual play in networks is to some extent boundedly rational, in the sense that coordination is influenced by local and individual factors, such as the number of (direct) neighbors, local clustering and individuals' risk attitudes. |
| Keywords: | networks, experiment, coordination, strategic substitutes, risk aversion |
| JEL: | C91 D00 D81 D85 C72 H41 |
| Date: | 2008–05 |
| URL: | http://d.repec.org/n?u=RePEc:use:tkiwps:0824&r=gth |
| By: | Marilda Sotomayor |
| Abstract: | Starting with an initial price vector, prices are adjusted in order to eliminate the demand excess and at the same time to keep the transfers to the sellers as low as possible. In each step of the auction, to which sellers should those transfers be made (minimal overdemanded sets) is the key definition in the description of the algorithm. Such approach was previously used by several authors. We introduce a novel distinction by considering multiple sellers owing multiple identical objects and multiple buyers with a quota greater than one consuming at most one unit of each seller’s good. This distinction induces a necessarily more complicated construction of the overdemanded sets than the constructions existing in the literature, even in the simplest case of additive utilities considered here. As the previous papers, our mechanism yields the minimum competitive equilibrium price vector. A procedure to find the maximum competitive equilibrium price vector is also provided. |
| Keywords: | matching; stable payoff; competitive equilibrium payoff; optimal stable payoff; lattice social costs; pure comparative vigilance; super-symmetric rule |
| Date: | 2008 |
| URL: | http://d.repec.org/n?u=RePEc:bro:econwp:2008-12&r=gth |
| By: | Marco Faillo (University of Trento - Faculty of Economics); Stefania Ottone (Università degli Studi di Milano-Bicocca); Lorenzo Sacconi (University of Trento - Faculty of Economics) |
| Abstract: | The main contribution of this paper is twofold. First of all, it focuses on the decisional process that leads to the creation of a social norm. Secondly, it analyses the mechanisms through which subjects conform their behaviour to the norm. In particular, our aim is to study the role and the nature of Normative and Empirical Expectations and their influence on people's decisions. The tool is the Exclusion Game, a sort of 'triple mini-dictator game'. It represents a situation where 3 subjects - players A - have to decide how to allocate a sum S among themselves and a fourth subject - player B - who has no decisional power. The experiment consists of three treatments. In the Baseline Treatment participants are randomly distributed in groups of four players and play the Exclusion Game. In the Agreement Treatment in each group participants are invited to vote for a specific non-binding allocation rule before playing the Exclusion Game. In the Outsider Treatment, after the voting procedure and before playing the Exclusion Game, a player A for each group (the outsider) is reassigned to a different group and instructed about the rule chosen by the new group. In all the treatments, at the end of the game and before players are informed about the decisions taken during the Exclusion Game by the other co-players, first order and second order expectations (both normative and empirical) are elicited through a brief questionnaire. The first result we obtained is that subjects' choices are in line with their empirical (not normative) expectations. The second result is that even a non-binding agreement induces convergence of empirical expectations - and, consequently, of choices. The third results is that expectation of conformity is higher in the partner protocol. This implies that a single outsider breaks the 'trust and cooperation' equilibrium. |
| Keywords: | fairness, social norms, beliefs, psychological games, experimental games |
| JEL: | C72 C91 A13 |
| Date: | 2008–07 |
| URL: | http://d.repec.org/n?u=RePEc:ent:wpaper:wp02&r=gth |
| By: | Umed Temurshoev (Department of Economics and SOM Research School, University of Groningen); ; |
| Abstract: | Ballester, Calvo-Armengol, and Zenou (2006, Econometrica, 74/5, pp. 1403-17) show that in a network game with local payoff complementarities, together with global uniform payoff substitutability and own concavity effects, the intercentrality measure identifies the key player - a player who, once removed, leads to the optimal change in overall activity. In this paper we search for the key group in such network games, whose members are, in general, different from the players with the highest individual intercentralities. Thus the quest for a single target is generalized to a group selection problem targeting an arbitrary number of players, where the key group is identified by a group intercentrality measure. We show that the members of a key group are rather nonredundant actors, i.e., they are largely heterogenous in their patterns of ties to the third parties. |
| Keywords: | social networks, centrality measures, intercentrality measures, clusters, policies |
| JEL: | A14 C72 L14 |
| Date: | 2008–09 |
| URL: | http://d.repec.org/n?u=RePEc:net:wpaper:0808&r=gth |
| By: | Laurent Bouton; Micael Castanheira |
| Abstract: | In elections, majority divisions pave the way to focal manipulations and coordination failures, which can lead to the victory of the wrong candidate. This paper shows how this flaw can be addressed if voter preferences over candidates are sensitive to information. We consider two potential sources of divisions: majority voters may have similar preferences but opposite information about the candidates, or opposite preferences. We show that when information is the source of majority divisions, Approval Voting features a unique equilibrium with full information and coordination equivalence. That is, it produces the same outcome as if both information and coordination problems could be resolved. Other electoral systems, such as Plurality and Two-Round elections, do not satisfy this equivalence. The second source of division is opposite preferences. Whenever the fraction of voters with such preferences is not too large, Approval Voting still satisfies full information and coordination equivalence. |
| Keywords: | Information Aggregation; Multicandidate Elections; Approval Voting; Poisson Games |
| JEL: | C72 D72 D81 D82 |
| Date: | 2008 |
| URL: | http://d.repec.org/n?u=RePEc:eca:wpaper:2008_017&r=gth |
| By: | Feri, Francesco (University of Innsbruck); Irlenbusch, Bernd (London School of Economics); Sutter, Matthias (University of Innsbruck) |
| Abstract: | The need for efficient coordination is ubiquitous in organizations and industries. The literature on the determinants of efficient coordination has focused on individual decision-making so far. In reality, however, teams often have to coordinate with other teams. We present an experiment with 825 participants, using six different coordination games, where either individuals or teams interact with each other. We find that teams coordinate much more efficiently than individuals. This finding adds one important cornerstone to the recent literature on the conditions for successful coordination. We explain the differences between individuals and teams using the experience weighted attraction learning model. |
| Keywords: | coordination games, individual decision-making, team decision-making, experience-weighted attraction learning, experiment |
| JEL: | C71 C91 C92 |
| Date: | 2008–10 |
| URL: | http://d.repec.org/n?u=RePEc:iza:izadps:dp3741&r=gth |
| By: | CHEIKBOSSIAN, Guillaume; SAND-ZANTMAN, Wilfried |
| JEL: | H7 C73 |
| Date: | 2008–07 |
| URL: | http://d.repec.org/n?u=RePEc:ide:wpaper:9498&r=gth |