High-Performance Embedded Computing

1.5 Models of Computation 43

The Petri net’s behavior is defined by a sequence of markings, each defining

a state of the net. The firing rule or transition rule determines the next state

given the current state. A transition is enabled if each input place of the transi-

tion is marked with at least as many tokens as are specified by the weight of

each incoming arc. Enabled transitions may fire but are not required to do so.

Firing removes tokens from the places that feed the transition equal to the

weight of the arc from the place to the transition and adds the same number of

tokens to each output place equal to the weight of the arc from the transitio ...