Petri Nets and Priorities

Priority speciications ooer a convenient description technique to resolve connicts in favour of particular actions. Besides specifying the functional behaviour of a system, priorities have also become important in the eld of performance analysis using stochastic Petri nets, where priorities are implicitly given by separating transitions into immediate and timed. For performance analysis of such stochastic Petri nets speciic properties, like liveness and existence of home states, are of major interest, because the latter , e.g., guarantees the applicability of a Markovian based analysis. Since several eecient analysis techniques have been developed for Petri nets without priorities, our interest is in carrying these techniques over to the priority case. This paper shows that positive properties of a net such as liveness and the existence of home states do also hold for the net with static priorities, if a simple condition is imposed on the priority relation. Topics: { Analysis and synthesis, structure and behaviour of nets { Functional analysis of stochastic Petri nets