Technical Report No. 90-06, pages 1-20 pp.. Hamilton, Ontario, Canada: McMaster University, Department of Computer Science and Systems, 1990.
Abstract: The authors introduce a new invariant semantics of concurrent systems which is a direct generalisation of the causal partial order semantics. This new approach overcomes some of the problems encountered when one uses causal partial orders alone. The authors discuss various aspects of the new invariant model. In particular, they show how the new invariants can be generated by 1-safe inhibitor and activator Petri nets.
Keywords: causal partial order semantics; 1-safe inhibitor net; activator net.