摘要：Fokkink ((1994) Inf. Process. Lett. 52: 333{337) has recently proposed a complete equational axiomatization of strong bisimulation equivalence for MPA_delta^*(A_tau), i.e., the language obtained by extending Milner's basic CCS with prefix iteration. Prefix iteration is a variation on the original binary version of the Kleene star operation p*q obtained by restricting the first argument to be an atomic action. In this paper, we extend Fokkink's results to a setting with the unobservable action by giving a complete equational axiomatization of Milner's observation congruence over MPA_delta^*(A_tau ). The axiomatization is obtained by extending Fokkink's axiom system with two of Milner's standard tau-laws and the following three equations that describe the interplay between the silent nature of tau and prefix iteration: tau . x = tau*x a*(x+tau.y) = a*(x+tau.y + a.y) tau.(a*x) = a*(tau.a*x) . Using a technique due to Groote, we also show that the resulting axiomatization is omega-complete, i.e., complete for equality of open terms. AMS Subject Classification (1991): 68Q40, 68Q42. CR Subject Classification (1991): D.3.1, F.3.2, F.4.2. Keywords and Phrases: Minimal Process Algebra, prefix iteration, equational logic, omega-completeness, observation congruence.
