A Note on the Characterization of Weak Bisimulation Congruence in CCS

Abstract The aim of the note is to give a new proof of the characterization of weak bisimulation congruence in Milner's CCS (Calculus of Communicating Systems). The proof is new in that it does not need the assumption that for a given agent P there is a label λ, for which P is not in the domain of λ ⇒ .