Read First: State A state change is a change in the relation instances (tuples) that an object participates in, in such a way that its changes state. For example, if Mary loses her job, it would affect her Employed state, but if she changes Employers, it would not. In each case, the tuple she participates in changes, but in one case the state rule for Employed is violated, but not in the other. The states before and after a state change are given by isPrestateFor/hasPrestate and hasPostState/isPostStateFor respectively.
Subtypes: Event_