Truthful Revelation Mechanisms for Simultaneous Common Agency Games

In games in which multiple principals contract simultaneously and non-cooperatively with the same agent, standard direct revelation mechanisms in which the agent reports his type(i.e. his exogenous private information) have been proven inadequate to characterize the entire set of equilibrium outcomes. This paper introduces a more general class of revelation mechanisms in which the agent reports also the contractual decisions he is inducing with the principals. We …rst show that such a class has the same nice properties as the class of all unrestricted menus: (i) for any equilibrium of any indirect game with arbitrary communication space for the principals, there exists a truthful equilibrium in the game in which the principals are restricted to o¤er revelation mechanisms that sustains the same outcomes; (ii) any truthful equilibrium is robust in the sense that it remains an equilibrium in any game in which the principalsstrategy space is enlarged. We next show how revelation mechanisms can be put to work in applications such as menu auctions, moral hazard settings, and competition in non-linear tariffs to identify necessary and sufficient conditions for the sustainability of outcomes as common agency equilibria.mechanism design, contracts, Revelation Principle.

Pure Strategies and No Externalities with Multiple Agents

This note considers two properties of common agency models - pure strategy equilibria with simple competition are robust and equilibria in mechanisms can be reproduced as equilibria with simple competition provided an appropriate no-externalities assumption holds. This note provides counter examples to both these theorems when there are multiple agents.

The origins of fair play

This paper gives a brief overview of an evolutionary theory of fairness. The ideas are fleshed out in Binmore's book 'Natural Justice' (Oxford University Press, New York, 2005.), which is itself a condensed version of his earlier two-volume book 'Game Theory and the Social Contract' (MIT Press, Cambridge, MA, 1994 and 1998)

Truthful Revelation Mechanisms for Simultaneous Common Agency Games

This paper considers games in which multiple principals contract simultaneously with the same agent. We introduce a new class of revelation mechanisms that, although it does not always permit a complete equilibrium characterization, it facilitates the characterization of the equilibrium outcomes that are typically of interest in applications (those sustained by pure-strategy profiles in which the agent's behavior in each relationship is Markov, i.e., it depends only on payoff-relevant information such as the agent's type and the decisions he is inducing with the other principals). We then illustrate how these mechanisms can be put to work in environments such as menu auctions, competition in nonlinear tariffs, and moral hazard settings. Lastly, we show how one can enrich the revelation mechanisms, albeit at a cost of an increase in complexity, to characterize also equilibrium outcomes sustained by non-Markov strategies and/or mixed-strategy profiles.Mechanism design, contracts, revelation principle, menus, endogenous payoff-relevant information