The formalization of process algebras usually starts with a minimal core of operators and rules for its transition system, and then relax the system to improve its usability and ease the proofs. In the calculus of communicating systems (CCS), the structural congruence plays this role by making e.g. parallel composition commutative and associative: without it, the system would be cumbersome to use and reason about, and it can be proven that this change is innocuous in a precise technical sense. For the two reversible calculi extending CCS, the situation is less clear: CCS with Communication Keys (CCSK) was first defined without any structural congruence, and then was endowed with a fragment of CCS's congruence. Reversible CCS (RCCS) made the choice of "backing in" the structural equivalence, that became part of the "minimal core" of the system. In this short oral communication, we would like to re-consider the status and role of the structural congruence in general, to question its role in RCCS in particular, and to ask the more general question of the structural equivalences legitimacy.

中文翻译：

---

通信系统可逆演算的结构等效性（口头交流）

过程代数的形式化通常从其转换系统的最小运算符和规则的核心开始，然后放松系统以提高其可用性并简化证明。在通信系统 (CCS) 的演算中，结构同余通过使例如并行组合可交换和关联来发挥这一作用：没有它，系统将难以使用和推理，并且可以证明这种变化在以下方面是无害的精确的技术意义。对于扩展 CCS 的两个可逆演算，情况不太清楚：CCS with Communication Keys (CCSK) 最初是在没有任何结构一致的情况下定义的，然后被赋予了 CCS 一致的片段。可逆 CCS (RCCS) 选择了“支持”结构等效性，这成为“