# Petri net

## 1 Definitions

A **Petri net** (also known as a place/transition net or P/T net) is one of several mathematical representations of discrete distributed systems. As a modeling language, it graphically depicts the structure of a distributed system as a directed bipartite graph with annotations. As such, a Petri net has place nodes, transition nodes, and directed arcs connecting places with transitions. Petri nets were invented in 1962 by Carl Adam Petri. ([1] Wikipedia, retrieved 17:29, 29 February 2008 (MET))

Petri Nets is a formal and graphical appealing language which is appropriate for modelling systems with concurrency and resource sharing. Petri Nets has been under development since the beginning of the 60'ies, where Carl Adam Petri defined the language. It was the first time a general theory for discrete parallel systems was formulated. The language is a generalisation of automata theory such that the concept of concurrently occurring events can be expressed (Petri Net FAQ, retrieved 17:29, 29 February 2008 (MET)).

Petri nets can be used to describe workflows. See also UML activity diagrams, a formalism with similar semantics.

## 2 Tools

See the List of Petri net tools

## 3 Links

- Petri nets world. (The purpose of the Petri Nets World is to provide a variety of online services for the international Petri Nets community)

### 3.1 Standards

- Joint Technical Committee on Information Technology (JTC1), of the International Organisation for Standardisation (ISO) and the International Electrotechnical Commission (IEC).
- ISO/IEC 15909-1:2004.
- Petri Net Markup Language (PNML) is part 2 of ISO/IEC 1509

- Petri Nets Standards (some more info)

### 3.2 Tutorials and introductions

- Petri net (Wikipedia).

- A course on workflow management, TU Eindhoven. in particular: Petri nets refresher

## 4 References

- Kindler, Ekkart (2006). Concepts, Status, and Future Directions. In E. Schnieder (ed.): Entwurf Komplexer Automatisierungssysteme, EKA 2006, 9. Fachtagung, Braunschweig, Germany, May 2006, pp. 35-55. (describes PNML)