Towards mobile processes in unifying theories

The paper presents a denotational semantics of mobile processes in Hoare & He's Unifying Theories of Programming (UTP). Process mobility is captured by the mobile assignment or communication of higher-order variables, in which both the source and the target are process-valued variables. Processes are moved around in the system by updating the target and losing the value of the source. The semantics can be used to guarantee the correctness of a set of algebraic of refinement laws for the step-wise development of mobile systems. We give an outline of this development method, present and prove some of the laws.