On the Redundancy of Condition/Event-Nets

Petri nets often contain unnecessary places whose existence does not affect the behavior of net. To detect such redundant places is important to analysis and design of nets. This paper deals with such reundancy of condition/event-nets (C/E-nets). Every C/E-net is composed of simple nets, containing only one condition, called atoms. Therefore the construction problem of C/E-nets with desired behavior is reduced to the search for constituent atoms of nets. This paper first clarifies the relation between the individual behavior of each constituent atom and that of the over-all net. It next defines a redundant atom and discusses its properties. On this discussion, the paper then proposes a method of finding redundant conditions in nets. It last shows a sufficient condition for a net constituent atom to be redundant.