Previous papers give accounts of quests for satisfactory formalizations of the classical informal notion of an algorithm and the contemporary informal notion of an interactive algoritm. In this paper, an attempt is made to generalize the results of the former quest to the contemporary informal notion of a concurrent algorithm. The notion of a concurrent proto-algorithm is introduced. The thought is that concurrent algorithms are equivalence classes of concurrent proto-algorithms under an appropriate equivalence relation. Three equivalence relations are defined. Two of them are deemed to be bounds for an appropriate equivalence relation and the third is likely an appropriate one. The connection between concurrency and non-determinism in the presented setting is also addressed.

翻译：先前的研究论文阐述了为经典非形式化算法概念及当代非形式化交互式算法概念寻求满意形式化表述的探索历程。本文尝试将前项探索的成果推广至当代非形式化的并发算法概念。文中引入了并发原型算法的概念，其核心思想在于：并发算法是在适当等价关系下并发原型算法所构成的等价类。本文定义了三种等价关系，其中两种被视为适当等价关系的边界条件，第三种则很可能构成合适的等价关系。此外，本文亦探讨了所提出框架中并发性与非确定性之间的关联。