Implementation of Walrasian expectations equilibria
In an exchange economy with differentially informed traders, Non-exclusivity of information (NEI) is the condition that each trader's private information be perfectly predictable by an outside observer who has observed the private information of all other traders. NEI is one of a set of conditions which, taken together, are sufficient for the implementability of fully revealing expectations equilibria. Here we show that this condition is in fact necessary for the weak implementation of a much broader class of Walrasian equilibria, herein called expectations equilibria.