As shown in Fan (Journal of Philosophical Logic, 48, 425–445, 2019), there are some similarities/resemblances between contingency and accident. Given this, one may naturally ask if we can unify the two operators to manifest all of their similarities/resemblances. In this article, instead of looking at the interactions between the two operators like in Fan (Journal of Philosophical Logic, 48, 425–445, 2019), we turn our attention to the resemblances between the two operators. We extend the unification method in Fan (Logic Journal of the IGPL, 2020) to the current setting. The main results include some model-theoretical ones, such as expressivity, frame definability, bisimulation, and some axiomatization ones.

如范（Journal of Philosophical Logic, 48 , 425–445, 2019）所示，偶然性和意外性之间存在一些相似之处。鉴于此，人们可能自然会问我们是否可以统一这两个运算符以显示它们的所有相似之处/相似之处。在本文中，我们没有像范（Journal of Philosophical Logic, 48 , 425–445, 2019）中那样关注两个运算符之间的交互，而是将注意力转向两个运算符之间的相似之处。我们将 Fan（ IGPL 的 Logic Journal ，2020）中的统一方法扩展到当前设置。主要结果包括一些模型理论的结果，例如表达性、框架可定义性、双模拟和一些公理化的结果。