Bad apples in symmetric repeated games
研究大群体对称非匿名重复博弈，发现当承诺类型采取“群体占优”行动时，反民间定理成立，例如自愿公共品供给不可能，但强制罚款可恢复供给。
We study large‐population repeated games where players are symmetric but not anonymous, so player‐specific rewards and punishments are feasible. Players may be commitment types who always take the same action. Even though players are not anonymous, we show that an anti‐folk theorem holds when the commitment action is “population dominant,” meaning that it secures a payoff greater than the population average payoff. For example, voluntary public goods provision in large populations is impossible when commitment types never contribute, even if monetary rewards can be targeted to contributors; however, provision is possible if noncontributors can be subjected to involuntary fines. A folk theorem under incomplete information provides a partial converse to our result. Along the way, we develop some general results on symmetric games with incomplete information and/or repeated play.