This paper shows that in private value environments, strategy-proofness and the rectangular property are necessary conditions for (full) robust implementation (Bergemann and Morris, 2011). As corollaries, we obtain the equivalence between robust and secure implementation (Saijo et al., 2007),...

We study the classic implementation problem under the behavioral assumption that agents myopically adjust their actions in the direction of better-responses or best-responses. First, we show that a necessary condition for recurrent implementation in better-response dynamics (BRD) is a small...

Sortition is the process of selecting decision makers or senators by a lottery. We introduce sortition in implementation theory by augmenting a mechanism with a kleroterion or lottery machine p that selects the senators. An outcome is implemented after consulting only the opinions of the...

We investigate the problem of Nash implementation in the presence of “partially honest” individuals. A partially honest player is one who has a strict preference for revealing the true state over lying when truthtelling does not lead to a worse outcome than that which obtains when lying. We...

We consider a mechanism design problem in economies with increasing returns. We construct a new class of rules, called w-hybrid rules, and characterize them by strategy-proofness, anonymity, envy-freeness, consumer sovereignty, and non-bossiness. We show that w-hybrid rules improve the supremal...

A contract auction establishes a contract between a center and one of the bidders. As contracts may describe many terms, preferences over contracts typically display indifferences. The Qualitative Vickrey Auction (QVA) selects the best contract for the winner that is at least as good for the...

An aggregation rule maps each profile of individual strict preference orderings over a set of alternatives into a social ordering over that set. We call such a rule strategy-proof if misreporting one's preference never produces a different social ordering that is between the original ordering...

A domain of preference orderings is a random dictatorship domain if every strategy-proof random social choice function satisfying unanimity defined on the domain is a random dictatorship. Gibbard (1977) showed that the universal domain is a random dictatorship domain. We ask whether an arbitrary...

A social choice function may or may not satisfy a desirable property depending on its domain of definition. For the same reason, different conditions may be equivalent for functions defined on some domains, while not in other cases. Understanding the role of domains is therefore a crucial issue...

A monopolist sells a good whose value depends on the number of buyers who adopt it as well as on their private types. The seller coordinates the buyersʼ adoption decisions based on their reported types, and charges them the price based on the number of adoptions. We study ex post implementable...