We introduce friend- and enemy-oriented hedonic games with strangers (FOHGS and EOHGS respectively), two classes of hedonic games wherein agents are classified as friends, enemies, or strangers under the assumption that strangers will become either friends or enemies ex post facto. For several notions of stability in FOHGS and EOHGS, we characterize the hardness of verification for possible and necessary stability. We characterize the hardness of deciding whether possibly and necessarily X stable partitions exist for a given stability notion X. We prove that necessarily internally stable partitions always exist and provide sufficient conditions for necessary contractual individual stability.

翻译：本文引入了面向朋友的陌生人享乐博弈与面向敌人的陌生人享乐博弈，这两类享乐博弈将智能体区分为朋友、敌人或陌生人，并假设陌生人最终会转变为朋友或敌人。针对FOHGS与EOHGS中的多种稳定性概念，我们刻画了验证可能稳定性与必要稳定性的计算复杂度。我们描述了在给定稳定性概念X下，判定是否存在可能X稳定划分与必要X稳定划分的困难性。我们证明了必要内部稳定划分始终存在，并为必要契约个体稳定性提供了充分条件。