A version of the situation calculus in which situations are represented as first-order terms is presented. Fluents can be computed from the term structure, and actions on the situations correspond to rewrite rules on the terms. Actions that only depend on or influence a subset of the fluents can be described as rewrite rules that operate on subterms of the terms in some cases. If actions are bidirectional then efficient completion methods can be used to solve planning problems. This representation for situations and actions is most similar to the fluent calculus of Thielscher \cite{Thielscher98}, except that this representation is more flexible and more use is made of the subterm structure. Some examples are given, and a few general methods for constructing such sets of rewrite rules are presented. This paper was submitted to FSCD 2020 on December 23, 2019.

中文翻译：

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通过术语重写的情境演算

提出了一种将情况表示为一阶项的情况演算版本。Fluents 可以从术语结构中计算出来，对情况的动作对应于术语的重写规则。仅依赖或影响 fluent 子集的操作可以描述为在某些情况下对术语的子项进行操作的重写规则。如果动作是双向的，那么可以使用有效的完成方法来解决规划问题。这种情况和动作的表示与 Thielscher \cite{Thielscher98} 的流利演算最相似，只是这种表示更灵活，并且更多地使用了子项结构。给出了一些示例，并介绍了构建此类重写规则集的一些通用方法。