Constraint Handling Rules (CHR) is both a theoretical formalism based on logic and a practical programming language based on rules. This book, written by the creator of CHR, describes the theory of CHR and how to use it in practice. It is supported by a website containing teaching materials, online demos, and free downloads of the language. After a basic tutorial, the author describes in detail the CHR language and discusses guaranteed properties of CHR programs. The author then compares CHR with other formalisms and languages and illustrates how it can capture their essential features. Finally, larger programs are introduced and analyzed in detail. The book is ideal for graduate students and lecturers, and for more experienced programmers and researchers, who can use it for self-study. Exercises with selected solutions, and bibliographic remarks are included at the ends of chapters. The book is the definitive reference on the subject.

KI2004wasthe27theditionoftheannualGermanConferenceonArti?cialInt- ligence, which traditionally brings together academic and industrial researchers from all areas of AI and which enjoys increasing international attendance. KI 2004 received 103 submissions from 26 countries. This volume contains the 30 papers that were ?nally selected for presentation at the conference. The papers cover quite a broad spectrum of "classical" subareas of AI, like na- ral language processing, neural networks, knowledge representation, reasoning, planning, and search. When looking at this year's contributions, it was exciting to observe that there was a strong trend towards actual real-world applications of AI technology. A majority of contributions resulted from or were motivated by applications in a variety of areas. Examples include applications of pl- ning, where the technology is being exploited for taxiway tra?c control and game playing; natural language processing and knowledge representation are enabling advanced Web-based information processing; and the integration of - sults from automated reasoning, neural networks and machine perception into robotics leads to signi?cantly improved capabilities of autonomous systems. The technical programme of KI 2004 was highlighted by invited talks from outstanding researchers in the areas of automated reasoning, robot planning, constraintreasoning, machinelearning, andsemanticWeb: Jorg ] Siekmann(DFKI andUniversityofSaarland, Saarbruc ] ken), MalikGhallab(LAAS-CNRS, Toulouse), Franco, is Fages (INRIA Rocquencourt), Martin Riedmiller (University of - nabru ]ck), andWolfgangWahlster(DFKIandUniversityofSaarland, Saarbruc ] ken). Their invited papers are also presented in this volume."

The book is a short, concise and complete presentation of constraint programming and reasoning. The use of constraints had its scientific and commercial breakthrough in the 1990s. Programming with constraints makes it possible to model and solve problems with uncertain, incomplete information and combinatorial problems, as they are abundant in industry and commerce, such as scheduling, planning, transportation, resource allocation, layout, design and analysis. The theoretically well-founded presentation includes application examples from real life. It introduces the common classes of constraint programming languages and constraint systems in a uniform way. Constraint solving algorithms are specified and implemented in the constraint handling rules language (CHR). This book is ideally suited as a textbook for graduate students and as a resource for researchers and practitioners. The Internet support includes teaching material, software, latest news and online use and examples of the CHR language.

The use of constraints had its scientific and commercial breakthrough in the 1990s. Programming with constraints makes it possible to model and specify problems with uncertain, incomplete information and to solve combi natorial problems, as they are abundant in industry and commerce, such as scheduling, planning, transportation, resource allocation, layout, design, and analysis. This book is a short, concise, and complete presentation of constraint programming and reasoning, covering theoretical foundations, algorithms, implementations, examples, and applications. It is based on more than a decade of experience in teaching and research about this subject. This book is intended primarily for graduate students, researchers, and practitioners in diverse areas of computer science and related fields, including programming languages, computational logic, symbolic computation, and ar tificial intelligence. The book is complemented by a web-page with teaching material, software, links, and more. We take the reader on a step-by-step journey through the world of constraint-based programming and constraint reasoning. Feel free to join in ... Acknowledgements Thorn thanks his wife Andrea and his daughter Anna - for everything. He dedicates his contribution to the book to the memory of his mother, Grete. Slim thanks his wife N abila and his daughters Shirine and Amira for their ongoing support and patience."

The ConstraintHandling Rules (CHR) languagecameto life morethan 15 years ago.Sincethen, ithasbecomeamajordeclarativespeci?cationandimplemen- tion language for constraint-based algorithms and applications. In recent years, the ?ve Workshops on Constraint Handling Rules have spurred the exchange of ideas within the CHR community, which has led to increased international collaboration, new theoretical results and optimized implementations. The aim of this volume of Lecture Notes in Ariti?cial Intelligence was to attract high-quality research papers on these recent advances in CHR. The 8 papersinthis issuewereselectedfrom11submissionsaftercarefulreviewingand subsequent revisions. Each paper was reviewd by three reviewers. The accepted papers represent some of the research teams on CHR around the world. It is not by accident that the currently most active research group is featured here with three articles. We also would have liked to see contributions from other CHR teams, but space is limited and the reviewers took their job seriously. After an introductory article that foreshadows an upcoming monograph on CHR, the accepted papers span a range of current research topics in the CHR community. It goes from extending the CHR language with search facilities and the related adaptive framework, and from generating rules from speci?cations of constraint solvers to implementing abductive probabilistic reasoning. They cover the theory that is a compositional semantics for CHR and ?nally describe e?cient implementations of CHR in traditional mainstream programming l- guages and compiler optimizations in the context of the re?ned semantics of CHR. Wewouldliketothanktheauthorsofsubmittedpapersandthemanyrevi- ers for their contribution in making this collection of research papers possible

Das Buch gibt einen kompakten, aber umfassenden UEberblick uber das Problemloesen und Programmieren mit Constraints (Randbedingungen). Diese aktuelle Programmiermethodik ermoeglicht es, Aufgaben direkt zu formulieren und effizient zu loesen. Sie gewinnt zusehends Bedeutung in Anwendungsbereichen wie Kombinatorische Suchprobleme (z.B. Zeitplanen, Layout-Optimierung), Berechnungen (Finanzanalyse), Simulation (Hardware-Verifikation) oder allgemein Schliessen und Rechnen mit ungenauer oder unvollstandiger Information (z.B. Kostenschatzung). Die theoretisch fundierte Darstellung mit Aufgaben und Anwendungsbeispielen aus der Praxis ist in der Lehre erprobt, aber auch fur Forscher und Praktiker von Nutzen.