无界Petri网的进程表达式

Process Expression of Unbounded Petri Net

借助进程网系统的概念 ,首先证明了无界Petri网Σ的进程与其进程网系统ΣP的语言之间存在一一映射关系 ,将求取Σ的进程表达式的问题转化成求取ΣP的语言问题 .由于ΣP的结构一般比较复杂 ,直接求取其语言仍然比较困难 .通过定义库所的指标函数 ,将结构复杂的ΣP分解成结构简单的子网系统 ,引入了语言的同步交运算 ,给出了利用这些子网系统求取结构复杂的ΣP语言的方法 ,从而得到了求取无界Petri网Σ的进程表达式的算法 .

The one-to-one mapping relationship is proved between the process expression of an unbounded Petri net ∑ and the language of its process net system ∑p, so we can express the language of ∑p in order to establish the process expression of ∑. However, it is not easy to describe the language behaviors of ∑p directly because its structure is usually complex. A new decomposition method for structure-complex Petri net by assigning an index to each place is introduced, with which ∑p can be decomposed into some structure-simple subnet systems. With these subnet systems, the language of ∑p can be expressed based on the synchronization intersection operation of languages. By the description of the language of ∑p, an algorithm to obtain the process expression of ∑ is obtained.