Reachability Analysis Using Net Unfoldings

We study four solutions to the reachability problem for 1safe Petri nets, all of them based on the unfolding technique. We de ne the problem as follows: given a set of places of the net, determine if some reachable marking puts a token in all of them. Three of the solutions to the problem are taken from the literature [McM92,Mel98,Hel99], while the fourth one is first introduced here. The new solution shows that the problem can be solved in time O(n^k), where n is the size of the prefix of the...