21 majster-cederbaum m, salger f . towards the hierarchical verification of reactive systems . theoretical computer science, 2004, 318 : 243-296.22 winskel g . an introduction to event structures . lecture notes in computer science 354, 1989, pp . 364-397.23 hoare c a r . communicating sequential processes, prentice-hall, 1985 本文分别在语法和语义层次上对动作精化进行了定义,并证明了这两个层次的动作精化在前述两种等价关系下,关于一种基于完全偏序的指称语义是一致的。