Institute of Software Engineering and Programming Languages

CHR Research Group

Constraint Handling Rules (CHR) is a concurrent committed-choice constraint logic programming language consisting of guarded rules that transform multi-sets of atomic formulas (constraints) until exhaustion. It was designed by Thom Fruehwirth in 1991. CHR can embed many rule-based formalisms and systems, and it can describe algorithms in a compact declarative way without compromising efficiency. The clean semantics of CHR ensures that several desirable properties hold for CHR programs and also facilitates sophisticated program analysis. CHR libraries exist for Prolog, Haskell, Java, Javascript, Python and C. CHR is also available online for experimentation with many example programs. More than 250 academic and industrial projects worldwide use CHR, and about 2500 research papers reference it.

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2017

80.
Richter, Frank; Gall, Daniel; Frühwirth, Thom
A Confluence Checker for Constraint Handling Rules with Persistent Constraints
Proceedings of the 21st International Conference on Applications of Declarative Programming and Knowledge Management (INAP)
21st International Conference on Applications of Declarative Programming and Knowledge Management (INAP)
Würzburg
19th to 21st September 2017
September 2017
File:pdfhttps://www.uni-ulm.de/fileadmin/website_uni_ulm/iui.inst.170/home/gall/publications/richter_gall_fru_inap_2017.pdf
79.
Frühwirth, Thom
Implementation of Logical Retraction in Constraint Handling Rules with Justifications
Proceedings of the 21st International Conference on Applications of Declarative Programming and Knowledge Management (INAP)
21st International Conference on Applications of Declarative Programming and Knowledge Management (INAP)
Würzburg
19th to 21st September 2017
September 2017
File:pdfhttps://www.uni-ulm.de/fileadmin/website_uni_ulm/iui.inst.170/home/fruehwirth/publications/2017_fru_inap.pdf
78.
Gall, Daniel; Frühwirth, Thom
A Decidable Confluence Test for Cognitive Models in ACT-R
In Stefania Costantini, Enrico Franconi, William Van Woensel, Roman Kontchakov, Fariba Sadri, and Dumitru Roman, Editor, Proceedings of RuleML+RR 2017Volume10364fromLecture Notes in Computer Science
International Joint Conference on Rules and Reasoning (RuleML+RR 2017)
London, UK
July 2017
In Stefania Costantini, Enrico Franconi, William Van Woensel, Roman Kontchakov, Fariba Sadri, and Dumitru Roman, Editor
Publisher: Springer
July 2017
DOI:10.1007/978-3-319-61252-2_9
File:http://arxiv.org/pdf/1705.08392
77.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
A Rule-Based Approach for Automatic Interaction Detection and Annotation
21st International Conference Information Visualisation (iV2017),
21st International Conference Information Visualisation (iV2017)
London, UK
July 2017
July 2017
DOI:10.1109/iV.2017.59
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/interaction_detection.pdf
76.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
CHR-Graph: A Platform for Animating Tree and Graph Algorithms
Poster at the 21st International Conference Information Visualisation (iV2017),
21st International Conference Information Visualisation (iV2017)
London, UK
July 2017
July 2017
DOI:10.1109/iV.2017.58
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/chr-graph.pdf

2016

75.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom; Gall, Daniel
Animating Cognitive Models and Architectures: A Rule-based Approach
The 2nd Global Conference on Artificial Intelligence (GCAI 2016), Berlin, Germany
Global Conference on Artificial Intelligence
Berlin
September 2016
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/CGAI_submit.pdf
74.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
A Rule Based Approach to teach Mathematics using Animation
RuleML 2016 Challenge of the 10th International Web Rule Symposium (RuleML 2016), New York, USA, July 2016.
July 2016
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/math-chr-ruleml-2016.pdf
73.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
A Rule-based Approach for Animating Java Algorithms
20th International Conference Information Visualisation (iV2016), Lisbon, Portugal, July 2016.
July 2016
DOI:10.1109/IV.2016.55
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/nada-iv2016-final.pdf
72.
Gall, Daniel; Frühwirth, Thom
Translation of Cognitive Models from ACT-R to Constraint Handling Rules
10th International Web Rule Symposium (RuleML 2016), New York, USA, July 2016
July 2016
DOI:10.1007/978-3-319-42019-6_15
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/gall-ruleml2016-final.pdf
71.
Frühwirth, Thom
Why Can't You Behave? Non-Termination Analysis of Direct Recursive Rules with Constraints
10th International Web Rule Symposium (RuleML 2016), New York, USA, July
July 2016
DOI:10.1007/978-3-319-42019-6_14
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/thom-ruleml-2016-full.pdf