Gradualism and Irreversibility
研究一类两人动态博弈，其中每个玩家的合作水平只能增加不能减少，刻画了有效对称均衡路径：行动随时间逐渐上升，最终收敛到低于一次性博弈有效水平的水平，即使折现率很小。
This paper considers a class of two-player dynamic games in which each player controls a one-dimensional action variable, interpreted as a level of cooperation. The dynamics are due to an irreversibility constraint: neither player can ever reduce his cooperation level. Payoffs are decreasing in one's own action, increasing in one's opponent's action. We characterize efficient symmetric equilibrium action paths; actions rise gradually over time and converge, when payoffs are smooth, to a level strictly below the one-shot efficient level, no matter how little discounting takes place. The analysis is extended to incorporate sequential moves and asymmetric equilibria. Copyright 2002, Wiley-Blackwell.