ECEASST

The Workshop on Petri Nets and Graph Transformations, which is currently at its second edition, is focussed on the mutual relationship between two prominent specification formalisms for concurrency and distribution, namely Petri nets and graph transformation systems. It belongs to the folklore that Petri nets can be seen as rewriting systems over (multi)sets, the rewriting rules being the transitions, and, as such, they can be seen as special graph transformation systems, acting over labelled discrete graphs. The basic notions of Petri nets like marking, enabling, firing, steps and step sequences can be naturally “translated ” to corresponding notions of graph transformation systems. Due to this close correspondence there has been a mutual influence between the two fields, which has lead to a fruitful cross-fertilisation. Several approaches to the concurrent semantics of graph transformation systems have been strongly influenced by the corresponding theories and constructions for Petri nets (see, e.g., [10]). For instance, the truly concurrent semantics of algebraic graph transformations presented in [3, 2] can be seen as a generalisation of the corresponding semantical constructions developed for Petri nets in [21, 14]. Similarly, the concurrent semantics for EMS systems in [12] is partly inspired by the Goltz-Reisig process semantics for Petri nets. More recently, various approaches to th