A.3 Common Operators

The operators in Table A.3 may be used in the definition of both processes and composite processes.

Table A.3: Common process operators
Conditional if then else	The process if B then P else Q behaves as the process P if the condition B is true; otherwise it behaves as Q. If the else Q is omitted and B is false, then the process behaves as STOP.
Re-labeling /	Re-labeling is applied to a process to change the names of action labels. The general form of re-labeling is:/{newlabel_1/oldlabel_1,... newlabel_n/oldlabel_n}.
Hiding \	When applied to a process P, the hiding operator {a₁..a_x } removes the action names a₁..a_x from the alphabet of P and makes these concealed actions “silent”. These silent actions are labeled tau. Silent actions in different processes are not shared.
Interface @	When applied to a process P, the interface operator @{a₁..a_x } hides all actions in the alphabet of P not labeled in the set a₁..a_x.