Much compact Time Petri Net state class spaces useful to restore CTL* properties

This paper deals with the verification of CTL* properties of Time Petri Nets (TPN model). To verify such properties, we need to contract the generally infinite state space of the TPN model into a finite graph that preserves its CTL* properties. Such a graph can be constructed using a partition refinement technique, where an intermediate graph, representing a contraction of the TPN state space, is first built then refined until CTL* properties are restored. Comparing to other approaches, we propose to construct much compact intermediate graphs. Experimental results have shown that our contractions are very appropriate to boost the refinement procedure. We have been able to reduce computation times by factors reaching four and more in certain cases. Resulting graphs have also been reduced in size.