In: Theoretical Computer Science, Vol. 55, No. 1, pages 87-136. 1987.
Abstract: Two ways of describing the behaviour of concurrent systems have widely been suggested: arbitrary interleaving and partial orders. Petri net theory offers a framework in which both kinds of semantics can be defined formally. Occurrence sequences correspond to interleaved behaviour while the notion of a process is used to capture partial-order semantics. This paper obtains formal results about the relationship between various classes of processes and occurrence sequences in net theory.