A theory of monitors

We develop a behavioural theory for monitors — software entities that passively analyse the runtime behaviour of systems so as to infer properties about them. First, we extend the monitor language and instrumentation relation of [17] to handle piCalculus process monitoring. We then identify contextual behavioural preorders that allow us to re-late monitors according to criteria defined over monitored executions of piCalculus processes. Subsequently, we develop alternative monitor pre-orders that are more tractable, and prove full-abstraction for the latter alternative preorders with respect to the contextual preorders.peer-reviewe