On the well-foundedness of adequate orders used for construction of complete unfolding prefixes

Petri net unfolding prefixes are an important technique for formal verification and synthesis of concurrent systems. In this paper we show that the requirement that the adequate order used for truncating a Petri net unfolding must be well-founded is superfluous in many important cases, i.e., it logically follows from other requirements. We give a complete analysis when this is the case. These results concern the very ‘core’ of the unfolding theory.