Deciding the Precongruence for Deadlock Freedom Using Operating Guidelines

In the context of asynchronously communicating and deadlock free services, the refinement relation of services has been formalized by the accordance preorder. A service Impl accords with a service Spec if every controller of Spec—that is, every environment that can interact with service Spec without deadlocking—is a controller of Impl . The procedure to decide accordance of two services uses that the set of controllers of a finite-state service has a finite representation, called operating guideline. Recently, it has been shown that the accordance preorder is not a precongruence and thus the decision procedure based on operating guidelines cannot be used. In this paper, we adapt the results on operating guidelines to the precongruence setting : We define an operating guideline that represents all controllers of a service w.r.t. the accordance precongruence and show how this refinement relation of two services can be decided based on their operating guidelines.