Transition Priority:

Consider the situation where S2 and T2 are active and the transition from Q2 to P2 is enabled. Even if the environment provides event G, which enables both transitions from S2 to S1 (note, condition in(T2) evaluates to true) and the transition from T2 to T1, the transition from Q2 to P2 is performed since it has higher priority (no non-determinism arises). Priority between transitions is determined by comparing the scopes of enabled transitions.