Informational diversity over time and the optimality of monetary equilibria

The temporal realizations of a random state variable in an overlapping generations model create an informational diversity between members of different generations and require a reexamination of the optimality that competitive equilibria might display in such an environment. Using an optimality criterion that reflects this informational diversity we prove the optimality of competitive equilibrium in a model with a fixed stock of fiat money, a single-spot market, and good endowments that follow a Markov process. The need for an optimality criterion that incorporates informational diversity is further motivated by studying the same model with the operation of complete contingent commodities markets.