Abstract. CBS is a simple and natural CCS-like calculus where processes speak one at a time and are heard instantaneously by all others. Speech is autonomous, contention between speakers being resolved nondeterministically, but hearing only happens when someone else speaks. Observationally meaningful laws di er from those of CCS. The change from handshake communication in CCS to broadcast in CBS permits several advances. 1 Priority, which attaches only to autonomous actions, is simply added to CBS in contrast to CCS, where such actions are the result of communication. 2 A CBS simulator runs a process by returning a list of values it broadcasts. This permits a powerful combination, CBS with the host language. It yields several elegant algorithms. Only processes with a unique response to each input are needed in practice, so weak bisimulation is a congruence. 3 CBS subsystems are interfaced by translators; by mapping messages to silence, these can restrict hearing and hide speech. ...
K. V. S. Prasad