189 research outputs found
Collusion-Resilient Revenue In Combinatorial Auctions
In auctions of a single good, the second-price mechanism achieves, in dominantstrategies, a revenue benchmark that is naturally high and resilient to anypossible collusion.We show how to achieve, to the maximum extent possible, the same propertiesin combinatorial auctions
Very Simple and Efficient Byzantine Agreement
We present a very simple, cryptographic, binary Byzantine-agreement protocol that, with n >= 3t+1 >= 3 players, at most t of which are malicious, halts in expected 9 rounds
Perfect Implementation
Privacy and trust aect our strategic thinking, yet they have not been precisely modeled in mechanism design. In settings of incomplete information, traditional implementations of a normal-form mechanism - by disregarding the players' privacy, or assuming trust in a mediator - may fail to reach the mechanism's objectives. We thus investigate implementations of a new type. We put forward the notion of a perfect implementation of a normal-form mechanism M: in essence, a concrete extensive-form mechanism exactly preserving all strategic properties of M, without relying on a trusted mediator or violating the privacy of the players. We prove that any normal-form mechanism can be perfectly implemented by a verifiable mediator using envelopes and an envelope-randomizing device (i.e., the same tools used for running fair lotteries or tallying secret votes). Differently from a trusted mediator, a veriable one only performs prescribed public actions, so that everyone can verify that he is acting properly, and that he never learns any information that should remain private
Knightian Analysis of the Vickrey Mechanism
We analyze the Vickrey mechanism for auctions of multiple identical goods
when the players have both Knightian uncertainty over their own valuations and
incomplete preferences. In this model, the Vickrey mechanism is no longer
dominant-strategy, and we prove that all dominant-strategy mechanisms are
inadequate. However, we also prove that, in undominated strategies, the social
welfare produced by the Vickrey mechanism in the worst case is not only very
good, but also essentially optimal.Comment: To appear in Econometric
Knightian Auctions
We study single-good auctions in a setting where each player knows his own
valuation only within a constant multiplicative factor \delta{} in (0,1), and
the mechanism designer knows \delta. The classical notions of implementation in
dominant strategies and implementation in undominated strategies are naturally
extended to this setting, but their power is vastly different.
On the negative side, we prove that no dominant-strategy mechanism can
guarantee social welfare that is significantly better than that achievable by
assigning the good to a random player.
On the positive side, we provide tight upper and lower bounds for the
fraction of the maximum social welfare achievable in undominated strategies,
whether deterministically or probabilistically
Rational Robustness for Mechanism Design
first draftThe currently prevailing equilibrium-based approach to mechanism design suffers from a plurality of fundamental problems, and new conceptual frameworks are needed to solve or sufficiently alleviate them. In this paper, we put forward rational robustness, a new solution concept/implementation notion that is not equilibrium-based; prove its fundamental structural theorems; and compare it with prior notions. Our notion of implementation is specifically built so as to be robust against the problem of equilibrium selection. We prove it robust against other fundamental problems as well in different papers.Work partially supported by ONR Contract Number N00014-09-1-0597
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