Weak Semantics Based on Lighted Button Pressing Experiments An Alternative Characterization of the Readiness Semantics

Imposing certain restrictions on the transition system that deenes the behaviour of a process allows us to characterize the readiness semantics of OH86] by means of black{box testing experiments, or more precisely by lighted button testing experiments BM92]. As divergence is considered we give the semantics as a preorder, the readiness preorder, which kernel coincides with the readiness equivalence of OH86]. This leads to a bisimu-lation like characterization and a modal characterization of the semantics. A concrete language, recursive free CCS without , is introduced, a proof system deened and it is shown to be sound and complete with respect to the readiness preorder. In the completeness proof the modal characterization plays an important role as it allows us to prove algebraicity of the preorder purely operationally.