Proving properties of interacting processes

Summary

The Set of Interacting Procedures (SIP) model, a graph model suitable for representing interacting computations, is presented. It includes nótation for creating and destroying processes, permits well-defined critical sections, and facilitates examining the logical properties of the modeled procedures. The essential parts of a theory of correctness of interacting processes are informally presented. These include a definition of correctness with respect to an assertion, a non-interference condition which justifies the use of the SIP model, and a set of sufficient conditions for correctness. To illustrate the use of the model and theory, a solution to the reader-writer problem is presented and modeled. An assertion expressing the correctness of the solution is formulated, and the SIP model of the solution is shown to be correct with respect to the assertion. Finally, the non-interference condition shows that the conclusions about the model also apply to the solution itself.