Deterministic Languages of Petri Nets

One way of using Petri nets for modelling systems is to represent states by markings, and actions that modify the states by transitions. In order to represent the fact that one event can cause different modifications of the system, one has to label the transitions. For example, in a school, the beginning and the end of classes are signalled, or labelled, by the ringing of a bell. One possible way of investigating the functioning of a system is to examine the sequences of labels corresponding to the firing sequences of transitions of the Petri net that models the system. Several classes of languages have been defined and studied: languages of sequences of firing of transitions when one event or signal causes one action, and languages of words labelling firing sequences of transitions when one event can cause several actions.