Finite supermodular design with interdependent valuations

This paper studies supermodular mechanism design in environments with arbitrary (finite) type spaces and interdependent valuations. In these environments, the designer may have to use Bayesian equilibrium as a solution concept, because ex-post implementation may not be possible. We propose direct (Bayesian) mechanisms that are robust to certain forms of bounded rationality while controlling for equilibrium multiplicity. In quasi-linear environments with informational and allocative externalities, we show that any Bayesian mechanism that implements a social choice function can be converted into a supermodular mechanism that also implements the original decision rule. The proposed supermodular mechanism can be chosen in a way that minimizes the size of the equilibrium set, and we provide two sets of sufficient conditions to this effect. This is followed by conditions for supermodular implementation in unique equilibrium.     

湖北省地方高校田径运动会改革的研究

运用文献资料法、调查法、数理统计等方法;从目前各高校校运动会的参与人数与满意度、参与目的、情意期望等方面,对湖北部分地方高校田径运动会的现状做出调查研究;并对其改革进行了探讨,使其能为地方高校田径运动的发展提供参考。     

Robust rational turnout

We show that equilibria of a class of participation games (Palfrey and Rosenthal in Public Choice 41(1):7–53, 1983; Journal of Public Economics 24(2):171–193, 1984) exhibit minimal heterogeneity of behavior so that players’ mixed strategies are summarized by at most two probabilities. We then establish that, except for a finite set of common costs of participation, these games are regular. Thus, equilibria of these voting games are robust to general payoff perturbations and survive in nearby games of incomplete information. Thanks to participants of the 2006 MPSA conference for comments on an early version.     

Reinforcement-Based Adaptive Learning in Asymmetric Two-Person Bargaining with Incomplete Information

The sealed bidk-double auction is a mechanism used to structure bilateral bargaining under two-sided incomplete information. This mechanism is tested in two experiments in which subjects are asked to bargain repeatedly for 50 rounds with the same partner under conditions of information disparity favoring either the buyer (Condition BA) or seller (Condition SA). Qualitatively, the observed bid and offer functions are in agreement with the Bayesian linear equilibrium solution (LES) constructed by Chatterjee and Samuelson (1983). A trader favored by the information disparity, whether buyer or seller, receives a larger share of the realized gain from trade than the other trader. Comparison with previous results reported by Daniel, Seale, and Rapoport (1998), who used randomly matched rather than fixed pairs, shows that when reputation effects are present this advantage is significantly enhanced. A reinforcement-based learning model captures the major features of the offer and bid functions, accounting for most of the variability in the round-to-round individual decisions.     

On large games with bounded essential coalition sizes

We consider games in characteristic function form where the worth of a group of players depends on the numbers of players of each of a finite number of types in the group. The games have bounded essential coalition sizes: all gains to cooperation can be achieved by coalitions bounded in absolute size (although larger coalitions are permitted they cannot realize larger per-capita gains). We show that the utility function of the corresponding "limit" market, introduced in Wooders (1988, 1994a) , is piecewise linear. The piecewise linearity is used to show that for almost all limiting ratios of percentages of player-types, as the games increase in size (numbers of players), asymptotically the games have cores containing only one payoff, and this payoff is symmetric (treats players of the same type identically). We use this result to show that for almost all limiting ratios of percentages of player-types, Shapley values of sequences of growing games converge to the unique limiting payoff.     

SPATIAL DISCRIMINATION,PRODUCT SUBSTITUTABILITY AND WELFARE

The paper examines a quantity–location duopoly game in a spatial discrimination model in which the delivered goods are assumed to be imperfect substitutes or complements. By extending the range of the unit transportation cost analysed in the existing literature, it is shown that a dispersed equilibrium arises in which the choice of the optimal locations is affected by the degree of product substitutability. The interaction between the latter and the size of the transportation cost is also discussed in order to verify its welfare implications. In particular, it is shown that in this spatial framework imperfect substitutability may increase welfare.     

Repeated signaling games

I analyze a class of repeated signaling games in which the informed player's type is persistent and the history of actions is perfectly observable. In this context, a large class of possibly complex sequences of signals can be supported as the separating equilibrium actions of the “strong type” of the informed player. I characterize the set of such sequences. I also characterize the sequences of signals in least cost separating equilibria (LCSE) of these games. In doing this, I introduce a state variable that can be interpreted as a measure of reputation. This gives the optimization problem characterizing the LCSE a recursive structure. I show that, in general, the equilibrium path sequences of signals have a simple structure. The shapes of the optimal sequences depend critically on the relative concavities of the payoff functions of different types, which measure the relative preferences towards payoff smoothing.     

Strategic Similarity and Emergent Conventions: Evidence from Similar Stag Hunt Games

This paper reports evidence on the origin of convention in laboratory cohorts confronting similar but not identical strategic situations repeatedly. The experiment preserves the action space of the game, while randomly perturbing the payoffs and scrambling the action labels in an effort to blunt the salience of retrospective selection principles. Hence, the similarity between stage games is reduced to certain strategic details, like efficiency, security, and risk dominance. Nevertheless, we do observe conventions emerging in half of the laboratory cohorts. When a convention emerges subjects's behavior conforms to the selection principles of efficiency rather than security or risk dominance. Journal of Economic Literature Classification Numbers: C72, C78, C92, D83.     

Strategic Interaction between Governments and Investors under Privatization Programs

This article analyses the strategic moves of governments and investors under privatization programs in a game‐theoretic context. In sequential‐move games of both perfect information and incomplete information, the best response of the strategic investors to observing a slow pace of privatization is to have a low participation in economic activity because of concerns over public policy credibility. This is true even if the government chooses to randomize its action to send mixed signals to the investors while adopting a slow pace of privatization for budgetary reasons. However, the outcome is Pareto inferior to a situation of phased but fast implementation of privatization programs and high private‐sector participation under plausible assumptions. Copyright © 2011 John Wiley & Sons, Ltd.     

信息不对称下的几个经济学实验

实验方法受到经济学界的重视,不对称信息条件下的实验方法研究具有重要现实意义。笔者探讨了若干在不对称信息条件下的经济学实验,包括名誉的作用、信号传递等重要实验,认为不对称信息下的实验的方法及其研究思路值得我国经济学者借鉴和深入研究。