Advanced Concurrent Constraint Languages: Application, Implementation and Methodology

ACCLAIM - 7195

Work Area: Logics and Logic Programming

Keywords concurrent constraint programming, symbolic computation, constraints, concurrency, parallelism

Start Date: 1 September 92 / Duration: 36 months / Status: running

[ participants / contact ]

Abstract This project aims to further the conceptual, mathematical and practical foundations of concurrent constraint programming, and in so doing, provide a framework for designing and implementing advanced computational tools for the development of complex, symbolic computational tasks in areas such as knowledge-representation and reasoning, design, diagnosis, simulation, scheduling, and natural language understanding.


ACCLAIM aims to:

Approach and Methods

ACCLAIM brings together an interdisciplinary team of the leading European researchers in this area. In addition, fruitful cooperation with leading US researchers is expected.

Progress and Results

For the first year, seventeen public deliverable reports have been produced, which are available on request from the coordinator. Most correspond to articles published in international journals and conferences.

Novel language designs have been investigated that better support the needs of applications based on constraints: AKL, Oz, LIFE, clp(FD), and CLP(PB). For these, sequential and parallel prototype implementations are being developed.

Several problem-oriented constraint systems have been defined: finite domain constraints (FD), feature tree constraints (FT), order-sorted feature constraints (OSF), piece-wise linear constraints, list constraints, interval constraints, and pseudo-boolean constraints (PB). For these, efficient constraint solving algorithms are being designed, analysed, and implemented.

Compile-time program analysis frameworks based on abstract interpretation have been proposed. These will benefit both parallel and sequential implementations by providing safe approximations of the runtime behaviour of programs.

The formal properties of programs have been analysed. For this purpose an algebraic semantics for a concurrent abstract machine (CHARM) has been developed, and a true-concurrency semantics for both indeterministic and nondeterministic programs has been provided.


The consortium expects to generate the technological base that will allow the development and deployment of path-breaking, semantically based, performance-efficient parallel systems for symbolic computation.

Latest Publications

Information Dissemination Activies

Project results have been published and presented in international journals and conferences. ACCLAIM organised a workshop on Concurrent Constraint Programming at ICLP'93 in Budapest (June 25, 1993). Partners of ACCLAIM are participating in the organisation of the conference Constraints in Computational Logics (September 6-8, 1994).

Further information about ACCLAIM is available from the ACCLAIM home page <URL:>.


Swedish Institute of Computer Science - S
Logic Programming Systems Laboratory
Isafjordsgatan 26
Box 1263
S - 164 28 Kista


Research Institute for Symbolic Computation - A
Katholieke Universiteit Leuven - B
Deutsches Forschungszentrum für Künstliche Intelligenz - D
Universidad Politécnica de Madrid - E
DEC Paris Research Laboratory - F
INRIA-Roquencourt - F
Université d'Aix-Marseille II - F
Università di Pisa - I


Prof. S. Haridi
tel +46/8 752 1572
fax +46/8 751 7230

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ACCLAIM - 7195, August 1994

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html version of synopsis by Nick Cook