Mutex Causality in Processes and Traces of General Elementary Nets

A concurrent history represented by a causality structure that captures the intrinsic, invariant dependencies between its actions, can be interpreted as defining a set of closely related observations (e.g. step sequences). Depending on the relationships observed in the histories of a system, the concurrency paradigm to which it adheres may be identified, with different concurrency paradigms underpinned by different kinds of causality structures. Adding mutex arcs to elementary net systems with inhibitor arcs yields a system model enim-systems) that through its process semantics and associated causality structures fits the least restrictive concurrency paradigm. Here we complete the picture by giving an abstract description of the behaviour of an enim-system by grouping together step sequences in equivalence classes (generalised comtraces) using the structural relations between its transitions. The thus defined concurrent histories of the enim-system correspond exactly to the generalised stratified order structures underlying its processes. The results presented establish a link between enim-systems and trace theory and allow one to identify different observations of concurrent behaviour in a way that is consistent with the causality semantics defined by the operationally defined processes. © 2011 Newcastle University. Printed and published by Newcastle University, Computing Science, Claremont Tower, Claremont Road, Newcastle upon Tyne, NE1 7RU, England. Bibliographical details KLEIJN, J., KOUTNY, M. Mutex Causality in Processes and Traces of General Elementary Nets [By] J. Kleijn, M. Koutny Newcastle upon Tyne: Newcastle University: Computing Science, 2011. (Newcastle University, Computing Science, Technical Report Series, No. CS-TR-1286)