Preferential choice and coordination conditions

We present a process algebra with conditional expressions of which the conditions concern the enabledness of actions in the context in which a process is placed. With those conditions, it becomes easy to model preferential choices. A preferential choice of a process is a choice whereby certain alternatives are excluded if at least one of the other alternatives is permitted by the context in which the process is placed. Preferential choices are often modelled rather indirectly using a priority mechanism.