Event Structures for Arbitrary Disruption

In process algebras that allow for some form of disruption, it is important to state when a process terminates. One option is to include a termination action Ö. Another approach is that the `final' executed action of a process terminates the process. The semantics of the former approach has been investigated in the literature in detail, e.g. by providing consistent true-concurrency and operational descriptions. The `final' executed action termination approach, which is more adequate for modelling, still lacks the existence of a detailed true concurrent description. In order to give a true concurrency model of such a termination view, we introduce a new class of event structures. This type of event structures models disabling by indicating sets of precursor events. We show that the introduced class of event structures has more expressive power with respect to event traces than the common event structures. We also give a classification of the expressive power in terms of sets of event traces. A consistency result of an operational and a denotational semantics is shown.