We consider the computational complexity of the market equilibrium problem by exploring the structural properties of the Leontief exchange economy. We prove that, for economies guaranteed to have a market equilibrium, finding one with maximum social welfare or maximum individual welfare is NP-hard. In addition, we prove that counting the number of equilibrium prices is #P-hard.

We view achieving a particular correlated equilibrium distribution for a normal form game as an implementation problem. We show, using a parametric version of the two-person Chicken game and a wide class of correlated equilibrium distributions, that a social choice function that chooses a particular correlated equilibrium distribution from this class does not satisfy the Maskin monotonicity con...

In this paper, we explore the dynamic properties of an endogenous growth model with finite patent length. We show that there exists a unique equilibrium growth path and that this path exhibits damped oscillations in contrast to the equilibrium path of an endogenous growth model with infinite patent length.We also examine the effects of patent policy on social welfare and show that infinite pate...

We study if (and when) the intersections and unions of social choice rules that are implementable with respect to a certain equilibrium concept are themselves implementable with respect to that equilibrium concept. While the results for dominant strategy equilibrium are mostly of negative nature, the situation is di¤erent in the case of Nash implementation. We …nd that the union of any set of N...

M disclose quality information directly to potential consumers using a variety of communication channels. This study investigates how competition may influence duopoly firms’ incentive to voluntarily reveal quality information. We show that firms in competitive markets reveal less information than a monopoly firm. In addition, sequential disclosure leads to asymmetric equilibrium disclosure beh...

Consider the problem of exact Nash Implementation of social choice correspondences. De…ne a lottery mechanism as a mechanism in which the planner can randomize on alternatives out of equilibrium while pure alternatives are always chosen in equilibrium. When preferences over alternatives are strict, we show that Maskin monotonicity (Maskin, 1999) is both necessary and su¢ cient for a social choi...

We analyze the determinants of trust and trustworthiness in a matching equilibrium when agents have heterogeneous predispositions towards trusting and trustworthy behavior, there is transmission of information via both individual and collective reputations, and successful matches may persist. In new matches, more social trustworthiness breeds more individual trust. However, whether more social ...

Rotten Kids with Bad Intentions We examine a "Rotten Kid" model (Becker 1974) where a player with social preferences interacts with an egoistic player. We assume that social preferences are intention-based rather than outcome-based. In a very general multi-stage setting we show that any equilibrium must involve mutually unkind behavior of both players, endogenously generating negative emotions ...

We consider a Cournot oligopoly model where multiple suppliers (oligopolists) compete by choosing quantities. We compare the social welfare achieved at a Cournot equilibrium to the maximum possible, for the case where the inverse market demand function is convex. We establish a lower bound on the efficiency of Cournot equilibria in terms of a scalar parameter derived from the inverse demand fun...

This paper examines the problem of repeatedly implementing an efficient social choice function when the agents' preferences evolve randomly. We show that the freedom to set different mechanisms at different histories can give the planner an additional leverage to deter undesirable behavior even if the mechanisms are restricted to be simple and finite. Specifically, we construct a (history-depen...