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

Foreigners, Immigrants, Host Cities: The Policies of Multi-Ethnicity in Rome. Reading Governance in a Local Context

This paper reviews the experience of Rome in dealing with the challenges posed by a multi-ethnic society. A central feature of the local political strategy is the “Pact of Integration”. The adoption of the Pact proposes governance as a model of participation including many actors, namely immigrant communities, in the comprehensive development of the quality of life of the city and not only in the decision-making mechanisms of local powers. The Pact represents a contract by which the social and political acceptance of foreigners in the local environment is perceived as benefiting both the foreign and autochthonous communities. On one hand, immigrants are incorporated into their local environment, following from the recognition of foreigners’ rights and needs for solidarity. On the other hand, foreigners are considered agents of local development insofar as they are both consumers and producers. The multiethnic society can then be a source of development. The preface by Franca Eckert Coen provides an overview of the city’s experiences in managing religious differences.Immigration, Governance, Multi-ethnicity