For questions regarding the syntax, please contact Maximilien Colange, Fabrice Kordon, or Yann Thierry-Mieg.

The presentation of the syntax is divided in two parts:

• The arc valuation attribute,
• The place marking attribute.

A precise (and formal) definition can be found here for Place Transition Nets :

• “Petri Nets for Systems Engineering: A Guide to Modeling, Verification, and Applications (Part II)”, C. Girault and R. Valk (editors), Springer Verlag, 2003,

Wikipedia also offers some useful basic definitions.

Grammar: Basic Elements

The grammar is presented as a Backus-Naur form.

First of all, let us define some elements of the grammar:

<PositiveInteger> ::= any sequence of numeric character which value > 0
<NaturalInteger>  ::= any sequence of numeric character which value ? 0

Grammar for Arc Valuations

<ArcLabel> ::= <PositiveInteger>

Grammar for Place Marking

<InitialMarking> ::= <NaturalInteger>