摘要: Can extrinsic uncertainty ("animal spirits," "market psychology," "sunspots,"...) play a significant role in rational expectations equilibrium models? We establish that cannot matter the static Arrow-Debreu economy with complete markets. But we also can overlapping-generations markets but where market participation is limited to those consumers alive when are open. Equilibrium allocations which plays no Pareto optimal traditional sense. does (weaker) sense appropriate dynamic analysis.