Stratified causal theories for reasoning about deterministic devices and protocols

We present a method for formalising the behaviour of simple deterministic devices and protocols in a way that makes explicit the causal dependencies amongst the component elements, thereby allowing true causal (as opposed to purely temporal) reasoning. Our intention is to handle such systems effectively in the simplest possible way, without invoking additional problematic considerations (concerning, for example, non-monotonicity) that may be necessary for modelling a more general range of scenarios.