Weak and Strong Fairness in CCS

Abstract We examine the issue of weak and strong fairness in the framework of Milner's CCS. Our approach is operational. We address the problem of giving sets of finite rules for generating all and only the admissible execution sequences when fairness is assumed. We achieve our aims by defining two calculi, one for weak and the other for strong fairness. Both calculi are extensions of standard CCS. In neither case do we appeal to random assignment or to transformations. A distinguishing feature of the weak fair calculus, unlike standard approaches which appeal to random assignment, is that it does not involve predictive choice.