Efficient compromising

Two agents must select one of three alternatives. Their ordinal rankings are commonly known and diametrically opposed. Efficiency requires choosing the alternative the agents rank second whenever the weighted sum of their von Neumann Morgenstern utilities is higher than under either agent's favorite alternative. The agents' utilities of the middle-ranked alternative are i.i.d., privately observed random variables. In our setup, which is closely related to a public goods problem where agents face liquidity constraints but no participation constraints, decision rules that truthfully elicit utilities and implement efficient decisions do not exist. We provide analytical and numerical results on second-best rules.     

Non-computable strategies and discounted repeated games

Summary A number of authors have used formal models of computation to capture the idea of bounded rationality in repeated games. Most of this literature has used computability by a finite automaton as the standard. A conceptual difficulty with this standard is that the decision problem is not closed. That is, for every strategy implementable by an automaton, there is some best response implementable by an automaton, but there may not exist any algorithm forfinding such a best response that can be implemented by an automaton. However, such algorithms can always be implemented by a Turing machine, the most powerful formal model of computation. In this paper, we investigate whether the decision problem can be closed by adopting Turing machines as the standard of computability. The answer we offer is negative. Indeed, for a large class of discounted repeated games (including the repeated Prisoner's Dilemma) there exist strategies implementable by a Turing machine for whichno best response is implementable by a Turing machine.The work was begun while Nachbar was a visitor at The Center for Mathematical studies in Economics and Management Science at Northwestern University; he is grateful for their hospitality. We are also grateful to Robert Anderson and Neil Gretsky and to seminar audiences at UCLA for useful comments, and to the National Science Foundation and the UCLA Academic Senate Committee on Research for financial support. This paper is an outgrowth of work reported in Learning and Computability in Discounted Supergames.     

Dissolving a partnership (un)fairly

Summary. In an incomplete information, common values setting with risk-neutral agents, we consider mechanisms for allocating the assets of a dissolving partnership where the mechanism designer has no information about the distribution of signals of the agents. We find that the divide and choose mechanism systematically favors the chooser and hence fails on the grounds of fairness. We also examine the fairness properties of the winning and losing bid auctions and show that they systematically favor winning (resp. losing) bidder in ex post allocation of surplus. Finally, we show that a binding arbitration mechanism implements fair allocations.Received: 17 May 2002, Revised: 5 June 2003, JEL Classification Numbers: D39, D44I thank an anonymous referee for extremely helpful suggestions. I also gratefully acknowledge the support of the National Science Foundation and the Hoover Institution.     

战略性新兴产业区域集聚的范式演进与实现机理

在分析产业集聚中技术产业范式的基础上,认为战略性新兴产业集聚将遵循“突破性技术创新—产业重塑—产业空间集聚”的技术产业范式。基于此,分析了战略性新兴产业区域集聚的演进机理,并提出了促进中国战略性新兴产业区域集聚的政策建议。     

Green auctions: A biodiversity study of mechanism design with externalities

This paper uses a mechanism design approach to study the biodiversity improvement in a territory, where the government is the principal and the landholders are the agents. In particular, I analyze an optimal mechanism that considers multidimensional bid which includes both the biodiversity improvement of the project and its cost. Additionally, this mechanism incorporates the externality (either positive or negative) that a biodiversity project causes in the surrounding agents who decided not to participate. Specifically, I assume that externalities enter in the cost function of the nonparticipating landholders. I show that, in the case of negative externalities, the government will implement a transfer function which is decreasing in the landholder's efficiency level. On the other hand, in the case of a positive externality, paradoxically the government may be interested in the nonparticipation of the most efficient landholders.     

Designing an optimal contest

The paper brings a mechanism design perspective to the study of contests. We consider the problem of selecting a contest success function when the contest designer may also value the prize. We show that any equilibrium outcome that can be achieved by a concave increasing contest success function can be replicated by a linear contest success function. An expected utility maximizing designer should employ a linear homogeneous contest success function. We explicitly derive the optimal contest for a risk-neutral designer and present comparative statics results. Tullock's contest is optimal only when the designer's valuation for the prize is low.     

Computationally-feasible truthful auctions for convex bundles

In many economic settings, like spectrum and real-estate auctions, geometric figures on the plane are for sale. Each bidder bids for his desired figure, and the auctioneer has to choose a set of disjoint figures that maximizes the social welfare. In this work, we design mechanisms that are both incentive compatible and computationally feasible for these environments. Since the underlying algorithmic problem is computationally hard, these mechanisms cannot always achieve the optimal welfare; Nevertheless, they do guarantee a fraction of the optimal solution. We differentiate between two information models—when both the desired figures and their values are unknown to the auctioneer or when only the agents' values are private data. We guarantee different fractions of the optimal welfare for each information model and for different families of figures (e.g., arbitrary convex figures or axis-aligned rectangles). We suggest using a measure on the geometric diversity of the figures for expressing the quality of the approximations that our mechanisms provide.     

Incentives for budget discipline in the presence of elections

This paper presents a mechanism to mitigate the adverse consequences of the political budget cycle on social welfare. We use a simplified two-period version of Rogoff's [Rogoff, K., 1990. Equilibrium political budget cycles. American Economic Review 80, 21–36.] rational budget cycle model to address the normative issue of reducing the budget deficit in pre-electoral periods. A regulation consisting of a sanction scheme contingent on fiscal policy joint with a fixed transfer is shown to provide the appropriate incentives for budget discipline in the presence of elections.     

Asking questions

We examine a model of limited communication in which the seller is selling a single good to two potential buyers. In each of the finite number of periods the seller asks one of the two buyers a binary question. After the final answer, the allocation and the transfers are executed. The model sheds light on the communication protocols that arise in welfare maximizing mechanisms.     

Weak monotonicity and Bayes–Nash incentive compatibility

An allocation rule is called Bayes–Nash incentive compatible, if there exists a payment rule, such that truthful reports of agents' types form a Bayes–Nash equilibrium in the direct revelation mechanism consisting of the allocation rule and the payment rule. This paper provides a characterization of Bayes–Nash incentive compatible allocation rules in social choice settings where agents have multi-dimensional types, quasi-linear utility functions and interdependent valuations. The characterization is derived by constructing complete directed graphs on agents' type spaces with cost of manipulation as lengths of edges. Weak monotonicity of the allocation rule corresponds to the condition that all 2-cycles in these graphs have non-negative length. For the case that type spaces are convex and the valuation for each outcome is a linear function in the agent's type, we show that weak monotonicity of the allocation rule together with an integrability condition is a necessary and sufficient condition for Bayes–Nash incentive compatibility.     

A note on budget balance under interim participation constraints: the case of independent types

We provide a simple proof of the equivalence between ex ante and ex post budget balance constraints in Bayesian mechanism design with independent types when participation decisions are made at the interim stage. The result is given an interpretation in terms of efficient allocation of risk.     

Social choice and electoral competition in the general spatial model

This paper extends the theory of the core, the uncovered set, and the related undominated set to a general set of alternatives and an arbitrary measure space of voters. We investigate the properties of social preferences generated by simple games; we extend results on generic emptiness of the core; we prove the general nonemptiness of the uncovered and undominated sets; and we prove the upper hemicontinuity of these correspondences when the voters’ preferences are such that the core is nonempty and externally stable. Finally, we give conditions under which the undominated set is lower hemicontinuous.     

Implementing cooperative solution concepts: a generalized bidding approach

This paper provides a framework for implementing and comparing several solution concepts for transferable utility cooperative games. We construct bidding mechanisms where players bid for the role of the proposer. The mechanisms differ in the power awarded to the proposer. The Shapley, consensus and equal surplus values are implemented in subgame perfect equilibrium outcomes as power shifts away from the proposer to the rest of the players. Moreover, an alternative informational structure where these solution concepts can be implemented without imposing any conditions of the transferable utility game is discussed as well. The authors thank Yukihiko Funaki, Andreu Mas-Colell, David Pérez-Castrillo and Jana Vyrastekova for helpful discussions. We also appreciate the comments from the seminar and conference participants at Keele University, Tilburg University, University of Haifa, University of Warwick, CORE at Louvain-la-Neuve, Catholic University Leuven, Pablo de Olavide University in Seville, University of Vigo, the 2006 Annual Conference of the Israeli Mathematical Union in Neve Ilan, Israel, and the 61st European Meeting of the Econometric Society in Vienna, Austria in 2006. In particular, we are grateful to the associate editor and an anonymous referee. Their valuable comments and constructive suggestions contributed to a significant improvement of the paper. Wettstein acknowledges the financial support of the Pinchas Sapir Center for Development in Tel Aviv University.