Compositionality Concurrency And Partial Correctness

The hierarchical decomposition of programs into smaller ones is generally considered imperative to master the complexity of large programs. The impact of this principle of program decomposition on the specification and verification of parallel executed programs is the subject of this monograph. Two important yardsticks for verification methods, those of compositionality and modularity, are made precise. The problem of reusing software is addressed by the introduction of the notion of specification adaptation. Within this context, different methods for specifying the observable behavior with respect to partial correctness of communicating processes are considered, and in particular the contrast between the "programs are predicates" and the "programs are predicate transformers" paradigms is shown. The associated formal proof systems are proven sound and complete in various senses with respect to the denotational semantics of the programming language, and they are related to each other to give an in-depth comparison between the different styles of program verification. The programming language TNP used here is near to actual languages like Occam. It combines CCS/CSP style communication based programming with state based programming, and allows dynamically expanding and shrinking networks of processes.

This Festschrift volume, published in honor of Willem-Paul de Roever, contains 19 detailed papers written by the friends and colleagues of the honoree, all eminent scientists in their own right. These are preceded by a detailed bibliography and rounded off, at the end of the book, with a gallery of photographs. The theme under which the papers have been collected is Concurrency, Compositionality, and Correctness, reflecting the focus of Willem-Paul de Roever's research career. Topics addressed include model checking, computer science and state machines, ontology and mereology of domains, game theory, compiler correctness, fair scheduling and encryption algorithms.

An advanced 2001 textbook on verification of concurrent programs using a semantic approach which highlights concepts clearly.

This book constitutes the refereed proceedings of the 15th International Conference on Foundations of Software Technology and Theoretical Computer Science, FSTTCS '95, held in Bangalore, India in December 1995. The volume presents 31 full revised research papers selected from a total of 106 submissions together with full papers of four invited talks. Among the topics covered are algorithms, software technology, functional programming theory, distributed algorithms, term rewriting and constraint logic programming, complexity theory, process algebras, computational geometry, and temporal logics and verification theory.

The semantics of concurrent systems is one of the most vigorous areas of research in theoretical computer science, but suffers from disagree ment due to different, and often incompatible, attitudes towards abstracting non-sequential behaviour. When confronted with process algebras, which give rise to very elegant, highly abstract and com positional models, traditionally based on the interleaving abstraction, some argue that the wealth of contribution they have made is partially offset by the difficulty in dealing with topics such as faimess. On the other hand, the non-interleaving approaches, based on causality, although easing problems with fairness and confusion, still lack struc ture, compositionality, and the elegance of the interleaving counter parts. Since both these approaches have undoubtedly provided important contributions towards understanding of concurrent systems, one should concentrate on what they have in common, rather than the way they differ. The Intemational Workshop on Semantics for Concurrency held at the University of Leicester on 23-25 July 1990 was organised to help overcome this problem. Its main objective was not to be divisive, but rather to encourage discussions leading towards the identification of the positive objective features of the main approaches, in the hope of furthering common understanding. The Workshop met with an excel lent response, and attracted contributions from all over the world. The result was an interesting and varied programme, which was a combi nation of invited and refereed papers. The invited speakers were: Prof. dr. E. Best (Hildesheim University) Prof. dr. A.

This book originates from the International Symposium on Compositionality, COMPOS'97, held in Bad Malente, Germany in September 1997. The 25 chapters presented in revised full version reflect the current state of the art in the area of compositional reasoning about concurrency. The book is a valuable reference for researchers and professionals interested in formal systems design and analysis; it also is well suited for self study and use in advanced courses.

The research described in this monograph concerns the formal specification and compositional verification of real-time systems. A real-time programminglanguage is considered in which concurrent processes communicate by synchronous message passing along unidirectional channels. To specifiy functional and timing properties of programs, two formalisms are investigated: one using a real-time version of temporal logic, called Metric Temporal Logic, and another which is basedon extended Hoare triples. Metric Temporal Logic provides a concise notationto express timing properties and to axiomatize the programming language, whereas Hoare-style formulae are especially convenient for the verification of sequential constructs. For both approaches a compositional proof system has been formulated to verify that a program satisfies a specification. To deduce timing properties of programs, first maximal parallelism is assumed, modeling the situation in which each process has itsown processor. Next, this model is generalized to multiprogramming where several processes may share a processor and scheduling is based on priorities. The proof systems are shown to be sound and relatively complete with respect to a denotational semantics of the programming language. The theory is illustrated by an example of a watchdog timer.