均衡概念的提炼和形式化是博弈论学科创立的标志, 博弈论的发展是围绕各种均衡概念的基本性质展开的。一般认为, 均衡不存在是一个负面结果, 均衡不存在研究就没法推进。对于经济学研究而言也是如此。本文通过文献中非合作博弈和完全竞争市场中的两个例子说明, 有时候可以对均衡不存在给出有价值的解释。第一个例子通过网络硬币匹配博弈研究时尚现象的演化, 均衡不存在用来解读时尚周期的出现。第二个例子介绍的是完全竞争劳动力市场中公司与工人间的匹配问题, 均衡不存在用来解读提前签约现象。我们还简要介绍了Shapley关于效用可转移合作博弈核心为空集的精彩解读。

The refinement and formalization of equilibrium concepts mark the establishment of game theory as a distinct discipline. The development of game theory has been centered around the fundamental properties of various equilibrium concepts. It is generally accepted that the nonexistence of equilibrium is seen as a negative outcome, impeding the advancement of equilibrium research. This holds true for economic research as well. This paper illustrates, through two examples from the literature on non-cooperative games and perfectly competitive markets, that sometimes valuable interpretations can be provided for the nonexistence of equilibrium. The first example examines the evolution of fashion phenomena through a network game based on matching pennies, where the nonexistence of equilibrium is used to interpret the emergence of fashion cycles. The second example discusses the matching problem between companies and workers in a perfectly competitive labor market, where the nonexistence of equilibrium is used to explain the phenomenon of early contracting. Additionally, we briefly introduce Shapley's insightful interpretation regarding the empty core in transferable utility cooperative games.