Reference Work Entry

Encyclopedia of Database Systems

pp 2103-2108

Petri Nets

  • W. M. P. van der AalstAffiliated withEindhoven University of Technology


Place transition nets; Condition event nets; Colored nets


The Petri net formalism provides a graphical but also formal language which is appropriate for modeling systems and processes with concurrency and resource sharing. It was introduced in the beginning of the 1960's by Carl Adam Petri and was the first formalism to adequately describe concurrency. The classical Petri net is a directed bipartite graph with two node types called places and transitions. The nodes are connected via directed arcs. Places are represented by circles and transitions by rectangles. The network structure of the Petri net is static. However, places may contain tokens and the distribution of tokens of places may change as described in the firing rule. Petri nets have formal semantics and allow for all kinds of analysis. Moreover, due to the strong theoretical foundation much is known about the properties of different subclasses of Petri nets. Petri nets have been extended in ...

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