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Robust Mechanism Design
Author(s) -
Bergemann Dirk,
Morris Stephen
Publication year - 2005
Publication title -
econometrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 16.7
H-Index - 199
eISSN - 1468-0262
pISSN - 0012-9682
DOI - 10.1111/j.1468-0262.2005.00638.x
Subject(s) - equivalence (formal languages) , mechanism design , separable space , planner , computer science , interim , function (biology) , social choice theory , bellman equation , mechanism (biology) , mathematical optimization , mathematical economics , mathematics , artificial intelligence , discrete mathematics , political science , philosophy , epistemology , mathematical analysis , evolutionary biology , law , biology
The mechanism design literature assumes too much common knowledge of the environment among the players and planner. We relax this assumption by studying mechanism design on richer type spaces. We ask when ex post implementation is equivalent to interim (or Bayesian) implementation for all possible type spaces. The equivalence holds in the case of separable environments; examples of separable environments arise (1) when the planner is implementing a social choice function (not correspondence) and (2) in a quasilinear environment with no restrictions on transfers. The equivalence fails in general, including in some quasilinear environments with budget balance. In private value environments, ex post implementation is equivalent to dominant strategies implementation. The private value versions of our results offer new insights into the relationship between dominant strategy implementation and Bayesian implementation.