A valuation-based analysis of conflict-free Petri nets

We propose a novel valuation-based approach for analyzing conflict-free Petri nets. The basic idea is to associate a natural number, called the valuation, to each marking in the Petri net. If the set of markings of zero valuation is forward closed, then the valuation along any Petri net computation is nonincreasing, and in many cases, has the tendency to move towards zero valuation. Using the valuation-based method, we demonstrate a number of problems for conflict-free Petri nets to be decidable.