This paper is concerned with the amount of communication that must be provided to implement a performance standard by a mechanism whose stationary messages have the Nash property. In p articular, the authors study implementation of Walrasian allocations in exchange environments. They show that...

It is shown that if an economy's participants cannot be separated into groups across which there are no potentially conflicting interests--i.e., if the economy is "indecomposable"--then every continuous truth-dominant allocation mechanism will attain nonoptimal allocations on an open dense set...