Comparing trace expressions and linear temporal logic for runtime verification

Trace expressions are a compact and expressive formalism, initially devised for runtime verification of agent interactions in multiagent systems, which has been successfully employed to model real protocols, and to generate monitors for mainstream multiagent system platforms, and generalized to support runtime verification of different kinds of properties and systems. In this paper we formally compare the expressive power of trace expressions with the Linear Temporal Logic (LTL), a formalism widely adopted in runtime verification. We show that any LTL formula can be translated into a trace expression which is equivalent from the point of view of runtime verification. Since trace expressions are able to express and verify sets of traces that are not context-free, we can derive that in the context of runtime verification trace expressions are more expressive than LTL.