ABSTRACT. This paper deals with structuring mechanisms in Petri nets, with special emphasis on object orientation. Merging Petri nets and objects can bring some important benefits. It can solve both lack of modularity in Petri nets and lack of formality in object oriented paradigm. Proposed solution emphases simplicity and clarity of object oriented Petri nets definition. A language and system based on object oriented Petri nets is called PNtalk (right pronounciation is ``pee-an-talk'') and it can be used as a tool for modeling and simulation. Motivations to merging Petri nets and objects, used approach, and a brief description of PNtalk is presented in the paper.
KEYWORDS: Petri nets, Object orientation, Smalltalk, formal model, PNtalk.