Parametric trace expressions are a formalism expressly de- signed for parametric runtime verification (RV) which has been introduced and successfully employed in the context of runtime monitoring of multiagent systems.

Trace expressions are built on the general notion of event type, which allows them to be adopted in different contexts. In this paper we show how trace expressions can be used for conveniently specifying the expected behavior of a Java-like program to be monitored at runtime.

Furthermore, we investigate the basic properties of the primitive operators on which trace expressions are coinduc- tively defined in terms of a labeled transition system; this provides a basis for formal reasoning on equivalence of trace expressions and adopting useful optimization techniques to speed up runtime verification.