Joint debts are debts that more than one debtor guarantees mutually. They are sometimes interpreted as a version of the tragedy of the commons. However, a simple model of the dynamic tragedy of the commons fails to capture an important feature of joint debts. The authors model joint debts as a joint borrowing limit game and compare the model with the dynamic tragedy of the commons model. Thereby, the authors show the difference in the achievability of efficiency between these two models and present the conditions for efficiency. The conditions for efficiency are as follows: (i) a not too large economic disparity between the players; (ii) not too many players. The joint borrowing limit game has a broad range of applications because the model can be applied to a case where creditors and debtors expect a debt guarantee of someone unilaterally even without an explicit contract of joint debt. For example, this model can be applied to the Eurosystem that led to Greek overborrowing.

中文翻译：

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玩家能否避免共同债务游戏中的公地悲剧？

共同债务是多个债务人相互担保的债务。它们有时被解释为公地悲剧的一个版本。然而，动态公地悲剧的简单模型未能捕捉到共同债务的一个重要特征。作者将联合债务建模为联合借款限额博弈，并将该模型与公地模型的动态悲剧进行比较。因此，作者展示了这两种模型在效率可实现性上的差异，并提出了效率的条件。效率的条件如下： (i) 参与者之间的经济差距不大；(ii) 玩家不要太多。联合借款限额博弈的应用范围很广，因为该模型可以应用于债权人和债务人在没有明确的联合债务合同的情况下单方面期望某人获得债务担保的情况。例如，这个模型可以应用于导致希腊过度借贷的欧元体系。