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.

Klick here for more information on our research.

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.
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
73.
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
72.
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
71.
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

2015

70.
Gall, Daniel; Frühwirth, Thom
A Formal Semantics for the Cognitive Architecture ACT-R
, Revised Selected Papers of the 24th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2014)Volume8981
Publisher: Springer LNCS
September 2015
DOI:10.1007/978-3-319-17822-6_5
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/act-r-semantics-2015.pdf
69.
Sharaf, Nada; Abdennadher, Slim; Frühwirth, Thom
CHRAnimation: An Animation Tool for Constraint Handling Rules
, Revised Selected Papers of the 24th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2014)Volume8981
Publisher: Springer LNCS
September 2015
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/chr-animation-2015.pdf
68.
Zaki, Amira; Abdennadher, Slim; Frühwirth, Thom
Combining Forward and Backward Propagation
10th International Symposium on Frontiers of Combining Systems (FroCoS'15)
September 2015
DOI:10.1007/978-3-319-24246-0_19
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/zaki-frocos-2015.pdf
67.
Frühwirth, Thom
Constraint Handling Rules - What Else?
Invited Survey Paper, The 9th International Web Rule Symposium (RuleML)
August 2015
DOI:10.1007/978-3-319-21542-6_2
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/ruleML-keynote-chr-survey-15.pdf
66.
Frühwirth, Thom
A Devil's Advocate against Termination of Direct Recursion
ACM 17th International Symposium on Principles and Practice of Declarative Programming (PPDP 2015), Siena, Italy
July 2015
File:pdfhttp://www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/drafts/devils-advocate-ppdp-15.pdf