Deriving distributed systems using B-Method

Action systems is a formalism designed for the construction of parallel and distributed systems in a stepwise manner within the refinement calculus. In this paper we show how action systems can be derived and refined within a mechanical tool, the B-Toolkit. We describe how action systems are embedded in the B-Method, the method supported by the B-Toolkit. Furthermore, we show how a typical and nontrivial refinement rule, the superposition refinement rule, is formalized and applied on action systems within the B-Method. In addition to providing tool support for action systems refinement we also extend the application area of B-Method to cover parallel and distributed systems. A derivation towards a distributed load balancing algorithm is given as a case study.