Informational Constraints and the Overlapping Generations Model: Folk and Anti-Folk Theorems
分析在萨缪尔森消费贷款模型中，当代理人信息不完全时代际转移的可持续性。轻度信息约束下纯策略无法支持转移，混合策略虽能维持转移（类似民间定理），但这类均衡不稳健：若效用函数受微小随机扰动，混合策略均衡瓦解，仅零转移分配作为唯一理性结果存活。
This paper analyses the sustainability of inter-generational transfers in Samuelson's consumption-loan model when agents are imperfectly informed about past events. We find that with mild informational constraints, transfers cannot be supported by pure-strategy equilibria. Mixed strategies allow transfers to be sustained even if agents have little information, so that a version of the Folk theorem holds. However, these equilibria are not robust. If each agent's utility function is subjected to a small random perturbation as in Harsanyi (1973), these mixed strategy equilibria unravel, and only the zero-transfer allocation survives as the unique rationalizable outcome. This result is an example of mixed strategy equilibrium of an extensive form game which cannot be purified.