A critical challenge faced by the developer of a software system is to understand whether the system's components correctly integrate. While type theory has provided substantial help in detecting and preventing errors in mismatched static properties, much work remains in the area of dynamics. In particular, components make assumptions about their behavioral interaction with other components, but currently we have only limited ways in which to state those assumptions and to analyze those assumptions for correctness. We have formulated a method that begins to address this problem. The method operates at the architectural level so that behavioral integration errors, such as deadlock, can be revealed early and at a high level. For each component, a specification is given of its interaction behavior. Form this specification, assumptions that the component makes about the corresponding interaction behavior of the external context are automatically derived. We have defined an algorithm that performs compatibility checks between finite representations of a component's context assumptions and the actual interaction behaviors of the components with which it is intended to interact. A configuration of a system is possible if and only if a successful way of matching actual behaviors with assumptions can be found. The state-space complexity of this algorithm is significantly less than that of comparable approaches, and in the worst case, the time complexity is comparable to the worst case of standard rachability analysis.

This paper develops a semantic framework for concurrent languages with value passing. An operation analogous to substitution in the λ-calculus is given, and a semantics is given for a value-passing version of Milner's Calculus of Communicating Systems (CCS). An operational equivalence is then defined and shown to coincide with Milner's (early) bisimulation equivalence. We also show how semantics maybe given for languages with asynchronous communication primitives. In contrast with existing approaches to value passing, this semantics does not reduce data exchange to pure synchronization over (potentially infinite) families of ports indexed by data, and it avoids variable renamings that are not local to processes engaged in communication.

Abstract There can be different views of a concurrent distributed system, depending on who observes it. The final user may just want to know how the system behaves in terms of its possible sequences of actions, while the designer may want to know what are the sequential components of a system or how are they distributed in space. In other words, there is not a widely accepted single semantic model for concurrent systems. This paper describes a parametric verification tool for process description languages. It performs a symbolic execution of processes at different levels of abstraction and verifies deadlock and reachability properties. The tool also provides facilities to check behavioural equivalences. In addition to the classical interleaving semantics, truly concurrent approaches based on the notion of causality and locality are considered. This allows us to compare the expressive power of different models within the same environment. In this respect, we have verified many of the examples given in the literature using our tool.

Many approaches have been developed with the aim of capturing the advantages of both process algebras and Petri nets in terms of modularity and structure on one side and faithful description of concurrency on the other. A natural way of merging these