Multiplicity of mixed equilibria in mechanisms: A unified approach to exact and approximate implementation

Arbeitspapier

We characterize full implementation of social choice sets in mixedstrategy Bayesian equilibrium. Our results concern both exact and virtual mixed implementation. For exact implementation, we identify a strengthening of Bayesian monotonicity, which we refer to as mixed Bayesian monotonicity. It is shown that, in economic environments with at least three agents, mixed Bayesian implementation is equivalent to mixed Bayesian monotonicity, incentive compatibility and closure. For implementing a social choice function, the case of two-agents is also covered by these conditions and mixed Bayesian monotonicity reduces to Bayesian monotonicity. Following parallel steps, mixed virtual implementation is shown to be equivalent to mixed virtual monotonicity, incentive compatibility and closure. The key condition, mixed virtual monotonicity, is argued to be very weak. In particular, it is weaker than Abreu-Matsushima's measurability, thereby implying that: (1) virtual implementation in mixed Bayesian equilibrium is more permissive than virtual implementation in iteratively undominated strategies, and (2) non-regular mechanisms are essential for the implementation of rules in that gap.

Object Details

• Language: Englisch

References and Relationships

• Bibliographic citation: Series: Working Paper ; No. 2009-11

Classification and Topics

• Classification: Wirtschaft ; Noncooperative Games ; Positive Analysis of Policy Formulation and Implementation ; Asymmetric and Private Information; Mechanism Design
• Subject: exact implementation ; approximate implementation ; incomplete information ; incentive compatibility ; monotonicity ; Public Choice ; Unvollkommene Information ; Gleichgewichtstheorie

Contributors, Places and Time

• Event: Geistige Schöpfung
• (who): Serrano, Roberto ; Vohra, Rajiv
• Event: Veröffentlichung
• (who): Brown University, Department of Economics
• (where): Providence, RI
• (when): 2009

Further information

• Handle: http://hdl.handle.net/10419/62639
• Last update: 10.03.2025, 11:41 AM CET