CCS semantics via proved transition systems and rewriting logic

We consider (a slight variant of) the ccs calculus, and we analyze two operational semantics deened in the literature: the rst exploits Proved Transition Systems (pts) and the second Rewriting Logic (rl). We show that the interleaving interpretation of both semantics agree, in that they deene the same transitions and exhibit the same nondeterministic structure. In addition, we study causality in ccs computations. We recall the treatment via pts, that exhibits the notion of causality presented in the literature, and we show how to recast it in the rl semantics via suitable axioms.