Multiparty session types (MPST) provide a type discipline where a programmer or architect specifies a whole view of communications as a global protocol, and each distributed program is locally type-checked against its end-point projection. After 10 years from the birth of MPST, Scalas and Yoshida discovered that the proofs of type safety in the literature which use the end-point projection with mergeability are flawed. After this paper, researchers wrongly believed that the end-point projection (with mergeability) was unsound. We correct this misunderstanding, proposing a new general proof technique for type soundness of multiparty session $π$-calculus, which uses an association relation between a global type and its end-point projection.

翻译：多方会话类型（MPST）提供了一种类型规范，程序员或架构师将通信的整体视图指定为全局协议，每个分布式程序都根据其端点投影进行本地类型检查。在MPST诞生10年后，Scalas和Yoshida发现文献中使用可合并端点投影的类型安全性证明存在缺陷。此后，研究人员错误地认为（具有可合并性的）端点投影是不健全的。我们纠正了这一误解，提出了一种用于多方会话$π$-演算类型健全性的新通用证明技术，该技术利用了全局类型与其端点投影之间的关联关系。