ABSTRACT. The paper is a trial to describe a consistent path from Hierarhical to the Object Oriented Petri Nets. The aim of underlying research is to find a language environment suitable for system specification and prototyping. As a result, Object Oriented Petri Nets (OOPN) and the PNtalk language are defined. OOPN/PNtalk definition is based on the net invocation concept allowing the functional structuring of Petri nets. Object oriented structuring is defined as a modification of the functional one.
KEYWORDS: Petri nets, object orientation, rapid prototyping, formal specifications.