TSMTags, Events, Signals
Given a set of values V and a set of tags T, an event is TXV
A signal s is a set of events
A functional (or deterministic) signal is a (possibly partial) function from T to V
set of all s = S, a tuple of n signals = s, set of all such tuples = Sn
In timed system, T is totally ordered and in untimed system, T is partially ordered