Switching from Complete to Incomplete Information
28 Pages Posted: 29 Jul 2004
Date Written: November 2003
We construct an elementary mechanism (Dutta-Sen-Vohra, 1995) that Nash implements the Constrained Walrasian correspondence. We extend it to incomplete and non-exclusive information economies by enlarging the message space of agents. We characterize the set of Bayesian equilibrium outcomes of the mechanism, and thus characterize an extension of the Constrained Walrasian correspondence when one switches from complete to incomplete information. First, measurability restrictions on allocations do not emerge from the strategic behavior of agents: there exist simple economies for which the set of Constrained Rational Expectations equilibrium allocations is not contained in the set of equilibrium outcomes of the mechanism. Next, by imposing measurability restrictions on allocations, the mechanism globally implements the Constrained Rational Expectations Equilibrium correspondence. This result shows game-theoretic connections between these two market equilibrium concepts. However, it is obtained at the price of strong restrictions on the behavior of agents.
Keywords: Implementation, elementary mechanism, Walrasian equilibrium, Rational Expectations Equilibrium
Suggested Citation: Suggested Citation