We study the problem of implementing social choice correspondences using the concept of undominated Nash equilibrium, i.e. Nash equilibrium in which no one uses a weakly dominated strategy. We show that this mild refinement of Nash equilibrium has a dramatic impact on the set of implementable correspondences. Our main result is that if there are at least three agents in the society, then any co...

The Gibbard-Satterthwaite theorem implies the ubiquity of manipulators—the voters who could change the election outcome in their favor by unilaterally modifying their vote. In this paper, we ask what happens if a given profile admits several such voters. We model the strategic interactions among these voters, whom we call Gibbard-Satterthwaite manipulators, as a normal-form game. We classify th...

Chinese auctions are a combination between a raffle and an auction and are held in practice at charity events or festivals. In a Chinese auction, multiple players compete for several items by buying tickets, which can be used to win the items. In front of each item there is a basket, and the players can bid by placing tickets in the basket(s) corresponding to the item(s) they are trying to win....

We present a systematic study of Plurality elections with strategic voters who,in addition to having preferences over election winners, have secondary prefer-ences, which govern their behavior when their vote cannot affect the election out-come. Specifically, we study two models that have been recently considered in theliterature [6, 17]: lazy voters, who prefer to abstain when ...

This paper characterizes the properties of equilibrium location patterns in an Anderson-Neven-Pal model and uses these characteristics to comprehensively find the subgame perfect Nash equilibria, most of which are not yet found in the literature. Since the external competition effect may be exactly canceled out, or internal competition strictly dominates external competition, or the internal co...

In this paper we study the learning behavior of a population of boundedly rational players who interact by repeatedly playing an evolutionary game. A simple imitation type learning rule for the agents is suggested and it is shown that the evolution of the population strategy is described by the discrete time replicator dynamics with inertia. Conditions are derived which guarantee the local stab...

One problem associated with coevolutionary algorithms is that of forgetting, where one or more previously acquired traits are lost only to be needed later. We introduce a new coevolutionary memory mechanism to help prevent forgetting that is built upon game-theoretic principles, specifically Nash equilibrium. This “Nash memory” mechanism has the following properties: 1) It accumulates a collect...

We use laboratory experiments to compare allocation rules in uniform price divisible good auctions. “Standard” and “uniform” allocation rules admit different types of low-price equilibria, which are eliminated by a “hybrid” rule. We observe little evidence of revenue differences among the allocation rules. Under all three allocation rules, prices are competitive when bidders cannot explicitly c...

Though some economic environments provide allocation rules that are implementable in dominant strategies (strategy-proof), a significant number of environments yield impossibility results. On the other hand, while there are quite general possibility results regarding implementation in Nash or Bayesian equilibrium, these equilibrium concepts make strong assumptions about the knowledge that playe...

I analyze a model of a private value divisible good auction with different payment rules, standard rationing rule pro-rata on-the-margin and both with and without a restriction on the number of bids (steps) bidders can submit. I provide characterization of equilibrium bidding strategies in a model with restricted strategy sets and I show that these equilibria converge to some equilibrium of the...