Port-Synchronizable Test sequence(cont.)

Definition : Port-Synchronizable test sequence of an FSM
- For a transition T in a transition sequence E of an FSM,
  its port-predecessor transition, denoted as PPT(T,E):
  - If T is a timeout transition, then PPT(T,E) is null
  - otherwise, PPT(T,E) is the closest predecessor of T
    in E that involves the input port of T. If such a
    predecessor of T in E does not exist, then PPT(T,E)
    is null
- port - predecessor interval , denoted as PPI(T,E)
  - If T is a timeout transition, then PPI(T,E) is ƒÕ
  - If T is not a timeout transition and PPT(T,E) is null
    then PPI(T,E) is the sequence of transitions in E
    before T
  - If T is not a timeout transition and PPT(T,E) is not
    null, then PPI(T,E) is the sequence of transitions
    in E after PPT(T,E) and before T.