Order Structures for Subclasses of Generalised Traces

Traces are equivalence classes of action sequences which can be represented by partial orders capturing the causality in the behaviour of a concurrent system. Generalised traces, on the other hand, are equivalence classes of step sequences. They are represented by order structures that can describe non-simultaneity and weak causality, phenomena which cannot be expressed by partial orders alone. In this paper, we provide a systematic classification of different subclasses of generalised traces in terms of the order structures representing them. We also show how the original trace model fits into the overall framework.