We construct a Galois connection between the theories that underlie CCS and CSP. It projects the complete transition system for CCS onto exactly the subset that satisfies the healthiness conditions of CSP. The construction applies to several varieties of both calculi: CCS with strong, weak or barbed simulation, and CSP with trace refinement or failures refinement, or failures/divergence.We suggest the challenge of linking other theories of concurrency by Galois connection.
