
on Game Theory 
By:  Viossat, Yannick (Dept. of Economics, Stockholm School of Economics) 
Abstract:  A pure strategy is coherent if it is played with positive probability in at least one correlated equilibrium. A game is pretight if in every correlated equilibrium, all incentives constraints for non deviating to a coherent strategy are tight. We show that there exists a Nash equilibrium in the relative interior of the correlated equilibrium polytope if and only if the game is pretight. Furthermore, the class of pretight games is shown to include and generalize the class of twoplayer zerosum games. 
Keywords:  correlated equilibrium; Nash equilibrium; zerosum games; dual reduction 
JEL:  C72 
Date:  2006–08–29 
URL:  http://d.repec.org/n?u=RePEc:hhs:hastef:0641&r=gth 
By:  Demichelis, Stefano (Università degli studi di Pavia); Weibull, Jörgen (Dept. of Economics, Stockholm School of Economics) 
Abstract:  We here develop a model of preplay communication that generalizes the cheaptalk approach by allowing players to have a lexicographic preference, second to the payoffs in the underlying game, for honesty. We formalize this by way of an honesty (or truth) correspondence between actions and statements, and postulate two axioms met by natural languages. The model is applied to finite and symmetric twoplayer games and we establish that honest communication and play of the Pareto dominant Nash equilibrium together characterize the unique evolutionarily stable set in generic and symmetric n×ncoordination games. In particular, this holds even in Aumann's (1990) example of a Pareto dominant equilibrium that is not selfenforcing. 
Keywords:  efficiency; communication; coordination; honesty; evolutionary stability 
JEL:  C72 C73 D01 
Date:  2006–02–01 
URL:  http://d.repec.org/n?u=RePEc:hhs:hastef:0645&r=gth 
By:  Ziv Gorodeisky 
Date:  2006–12–03 
URL:  http://d.repec.org/n?u=RePEc:cla:levrem:321307000000000595&r=gth 
By:  CHRISTIAN, Robin; CONDER, Marston; SLINKO, Arkadii 
Abstract:  We show that every additively representable comparative probability order on n atoms is determined by at least n  1 binary subset comparisons. We show that there are many orders of this kind, not just the lexicographic order. These results provide answers to two questions of Fishburn et al (2002). We also study the flip relation on the class of all comparative probability orders introduced by Maclagan. We generalise an important theorem of Fishburn, Peke?c and Reeds, by showing that in any minimal set of comparisons that determine a comparative probability order, all comparisons are flippable. By calculating the characteristics of the flip relation for n = 6 we discover that the regions in the corresponding hyperplane arrangement can have no more than 13 faces and that there are 20 regions with 13 faces. All the neighbours of the 20 comparative probability orders which correspond to those regions are representable. Finally we define a class of simple games with complete desirability relation for which its strong desirability relation is acyclic, and show that the flip relation carries all the information about these games. We show that for n = 6 these games are weighted majority games. 
Keywords:  Additively reesentable linear orders, comrative obability, elicitation, subset comrisons, sime game, weighted majority game, desirability relation. 
Date:  2006 
URL:  http://d.repec.org/n?u=RePEc:mtl:montde:200618&r=gth 
By:  František Turnovec (Institute of Economic Studies, Faculty of Social Sciences, Charles University, Prague, Czech Republic) 
Abstract:  During last two decades we observe a boom of power indices literature related to constitutional analysis of European Union institutions and distribution of intrainstitutional and interinstitutional influence in the European Union decision making. Growing interest to power indices methodology leads also to reconsideration of the methodology itself. In this paper a new general a priori voting power measure is proposed distinguishing between absolute and relative power. This power measure covers traditional ShapleyShubik and PenroseBanzhaf power indices as its special cases. 
Keywords:  Absolute power; cooperative games; decisive situation; Ipower; pivot; power indices; Ppower; relative power; swing 
JEL:  D71 D74 
Date:  2005 
URL:  http://d.repec.org/n?u=RePEc:fau:wpaper:wp069&r=gth 
By:  Martin Shubik (Cowles Foundation, Yale University) 
Abstract:  An Axiomatization for Power and for Equity differ only in the addition of a Behind the Veil Axiom. 
Keywords:  Value, Behind the veil, Power, Equity, Ownership 
JEL:  C71 D63 
Date:  2006–11 
URL:  http://d.repec.org/n?u=RePEc:cwl:cwldpp:1593&r=gth 
By:  AMBEC, Steve; EHLERS, Lars 
Abstract:  With diminishing global water reserves the problem of water allocation becomes increasingly important. We consider the problem of efficiently sharing a river among a group of satiable countries. Inducing countries to efficiently cooperate requires monetary compensations via international agreements. We show that cooperation of the other countries exerts a positive externality on the benefit of a coalition. Our problem is to distribute the benefit of efficiently sharing the river under these constraints. If the countries outside of a coalition do not cooperate at all, then the downstream incremental distribution is the unique compromise between the absolute territorial sovereignty (ATS) doctrine and the unlimited territorial integrity (UTI) doctrine. If all countries outside of a coalition cooperate, then there may not exist any distribution satisfying the UTI doctrine. 
Keywords:  Water Allocation, Externalities 
JEL:  C71 D62 H23 
Date:  2006 
URL:  http://d.repec.org/n?u=RePEc:mtl:montde:200610&r=gth 