publications:
- title: "A Relation Algebraic Semantics for a Lazy Functional Logic Language"
  author:
  - name: "Bernd Braßel"
    link: "http://www.informatik.uni-kiel.de/prog/mitarbeiter/bernd-brassel/"
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  year: "2008"
  doi: "http://dx.doi.org/10.1007/978-3-540-78913-0_5"
  links:
    doi: "http://dx.doi.org/10.1007/978-3-540-78913-0_5"
  tags:
  - "laziness"
  - "semantics"
  - " algebra"
  - "logic"
  researchr: "https://researchr.org/publication/BrasselC08"
  cites: 0
  citedby: 0
  pages: "37-53"
  booktitle: "Relations and Kleene Algebra in Computer Science, 10th International Conference on Relational Methods in Computer Science, and 5th International Conference on Applications of Kleene Algebra, RelMiCS/AKA 2008, Frauenwörth, Germany, April 7-11, 2008. P"
  editor:
  - name: "Rudolf Berghammer"
    link: "https://researchr.org/alias/rudolf-berghammer"
  - name: "Bernhard Möller"
    link: "https://researchr.org/alias/bernhard-m%C3%B6ller"
  - name: "Georg Struth"
    link: "https://researchr.org/alias/georg-struth"
  volume: "4988"
  series: "Lecture Notes in Computer Science"
  publisher: "Springer"
  isbn: "978-3-540-78912-3"
  kind: "inproceedings"
  key: "BrasselC08"
- title: "A semantics for weakly encapsulated search in functional logic programs"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Michael Hanus"
    link: "https://researchr.org/alias/michael-hanus"
  - name: "Fabian Reck"
    link: "https://researchr.org/alias/fabian-reck"
  - name: "Daniel Seidel"
    link: "http://wob.iai.uni-bonn.de/Wob/en/view/class217_id1454.html"
  year: "2013"
  doi: "http://doi.acm.org/10.1145/2505879.2505896"
  links:
    doi: "http://doi.acm.org/10.1145/2505879.2505896"
    dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/ppdp/ChristiansenHRS13"
  researchr: "https://researchr.org/publication/ChristiansenHRS13"
  cites: 0
  citedby: 0
  pages: "49-60"
  booktitle: "15th International Symposium on Principles and Practice of Declarative Programming, PPDP '13, Madrid, Spain, September 16-18, 2013"
  editor:
  - name: "Ricardo Peña"
    link: "https://researchr.org/alias/ricardo-pe%C3%B1a"
  - name: "Tom Schrijvers"
    link: "https://researchr.org/alias/tom-schrijvers"
  publisher: "ACM"
  isbn: "978-1-4503-2154-9"
  kind: "inproceedings"
  key: "ChristiansenHRS13"
- title: "A purely functional implementation of ROBDDs in Haskell"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Frank Huch"
    link: "https://researchr.org/alias/frank-huch"
  year: "2006"
  tags:
  - "Haskell"
  researchr: "https://researchr.org/publication/ChristiansenH06%3A0"
  cites: 0
  citedby: 0
  pages: "55-71"
  booktitle: "Revised Selected Papers from the Seventh Symposium on Trends in Functional Programming, TFP 2006, Nottingham, United Kingdom, 19-21 April 2006"
  editor:
  - name: "Henrik Nilsson"
    link: "https://researchr.org/alias/henrik-nilsson"
  volume: "7"
  series: "Trends in Functional Programming"
  publisher: "Intellect"
  isbn: "978-1-84150-188-8"
  kind: "inproceedings"
  key: "ChristiansenH06:0"
- title: "Sloth - A Tool for Checking Minimal-Strictness"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  year: "2011"
  doi: "http://dx.doi.org/10.1007/978-3-642-18378-2_14"
  links:
    doi: "http://dx.doi.org/10.1007/978-3-642-18378-2_14"
    dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/padl/Christiansen11"
  researchr: "https://researchr.org/publication/Christiansen11"
  cites: 0
  citedby: 0
  pages: "160-174"
  booktitle: "Practical Aspects of Declarative Languages - 13th International Symposium, PADL 2011, Austin, TX, USA, January 24-25, 2011. Proceedings"
  editor:
  - name: "Ricardo Rocha"
    link: "https://researchr.org/alias/ricardo-rocha"
  - name: "John Launchbury"
    link: "https://researchr.org/alias/john-launchbury"
  volume: "6539"
  series: "Lecture Notes in Computer Science"
  publisher: "Springer"
  isbn: "978-3-642-18377-5"
  kind: "inproceedings"
  key: "Christiansen11"
- title: "EasyCheck - Test Data for Free"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Sebastian Fischer"
    link: "https://researchr.org/alias/sebastian-fischer"
  year: "2008"
  doi: "http://dx.doi.org/10.1007/978-3-540-78969-7_23"
  links:
    doi: "http://dx.doi.org/10.1007/978-3-540-78969-7_23"
  tags:
  - "testing"
  - "data-flow"
  researchr: "https://researchr.org/publication/ChristiansenF08"
  cites: 0
  citedby: 0
  pages: "322-336"
  booktitle: "Functional and Logic Programming, 9th International Symposium, FLOPS 2008, Ise, Japan, April 14-16, 2008. Proceedings"
  editor:
  - name: "Jacques Garrigue"
    link: "https://researchr.org/alias/jacques-garrigue"
  - name: "Manuel V. Hermenegildo"
    link: "https://researchr.org/alias/manuel-v.-hermenegildo"
  volume: "4989"
  series: "Lecture Notes in Computer Science"
  publisher: "Springer"
  isbn: "978-3-540-78968-0"
  kind: "inproceedings"
  key: "ChristiansenF08"
- title: "Minimally strict polymorphic functions"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Daniel Seidel"
    link: "http://wob.iai.uni-bonn.de/Wob/en/view/class217_id1454.html"
  year: "2011"
  doi: "http://doi.acm.org/10.1145/2003476.2003487"
  links:
    doi: "http://doi.acm.org/10.1145/2003476.2003487"
    dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/ppdp/ChristiansenS11"
  researchr: "https://researchr.org/publication/ChristiansenS11"
  cites: 0
  citedby: 0
  pages: "53-64"
  booktitle: "Proceedings of the 13th International ACM SIGPLAN Conference on Principles and Practice of Declarative Programming, July 20-22, 2011, Odense, Denmark"
  editor:
  - name: "Peter Schneider-Kamp"
    link: "https://researchr.org/alias/peter-schneider-kamp"
  - name: "Michael Hanus"
    link: "https://researchr.org/alias/michael-hanus"
  publisher: "ACM"
  isbn: "978-1-4503-0776-5"
  kind: "inproceedings"
  key: "ChristiansenS11"
- title: "Searching for deadlocks while debugging concurrent haskell programs"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Frank Huch"
    link: "https://researchr.org/alias/frank-huch"
  year: "2004"
  doi: "http://doi.acm.org/10.1145/1016850.1016858"
  links:
    doi: "http://doi.acm.org/10.1145/1016850.1016858"
  tags:
  - "Haskell"
  - "debugging"
  researchr: "https://researchr.org/publication/ChristiansenH04"
  cites: 0
  citedby: 0
  pages: "28-39"
  booktitle: "Proceedings of the Ninth ACM SIGPLAN International Conference on Functional Programming, ICFP 2004, Snow Bird, UT, USA, September 19-21, 2004"
  editor:
  - name: "Chris Okasaki"
    link: "https://researchr.org/alias/chris-okasaki"
  - name: "Kathleen Fisher"
    link: "http://www.research.att.com/people/Fisher_Kathleen_S"
  publisher: "ACM"
  isbn: "1-58113-905-5"
  kind: "inproceedings"
  key: "ChristiansenH04"
- title: "An Adequate, Denotational, Functional-Style Semantics for Typed FlatCurry"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Daniel Seidel"
    link: "http://wob.iai.uni-bonn.de/Wob/en/view/class217_id1454.html"
  - name: "Janis Voigtländer"
    link: "http://www.iai.uni-bonn.de/~jv/"
  year: "2010"
  doi: "http://dx.doi.org/10.1007/978-3-642-20775-4_7"
  abstract: "With the aim of putting type-based reasoning for functional logic languages, as recently explored by Christiansen et al. (PLPV 2010), on a formal basis, we develop a denotational semantics for a typed core language of Curry. Dealing with the core language FlatCurry rather than with full Curry suffices, since there exists a type-preserving translation from the latter into the former. In contrast to existing semantics for functional logic languages, we deliberately approach the problem \"from the functional side\". That is, rather than adapting approaches previously known from the study of (resolution-like) semantics for logic languages, we aim for a semantics in the spirit of standard denotational semantics for the polymorphic lambda calculus. We claim and set out to prove that the presented semantics is adequate with respect to an existing operational semantics. A particularly interesting aspect, we think, is that we give the first denotational treatment of recursive let-bindings in combination with call-time choice."
  links:
    doi: "http://dx.doi.org/10.1007/978-3-642-20775-4_7"
    dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/wflp/ChristiansenSV10"
  researchr: "https://researchr.org/publication/ChristiansenSV10"
  cites: 0
  citedby: 0
  pages: "119-136"
  booktitle: "Functional and Constraint Logic Programming - 19th International Workshop, WFLP 2010, Madrid, Spain, January 17, 2010. Revised Selected Papers"
  editor:
  - name: "Julio Mariño"
    link: "https://researchr.org/alias/julio-mari%C3%B1o"
  volume: "6559"
  series: "Lecture Notes in Computer Science"
  publisher: "Springer"
  isbn: "978-3-642-20774-7"
  kind: "inproceedings"
  key: "ChristiansenSV10"
- title: "Free theorems for functional logic programs: (abstract only)"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Daniel Seidel"
    link: "http://wob.iai.uni-bonn.de/Wob/en/view/class217_id1454.html"
  - name: "Janis Voigtländer"
    link: "http://www.iai.uni-bonn.de/~jv/"
  year: "2009"
  doi: "http://doi.acm.org/10.1145/1816027.1816035"
  abstract: "Type-based reasoning is popular in functional programming. In particular, parametric polymorphism constrains functions in such a way that statements about their behavior can be derived without consulting function definitions. Is the same possible in a strongly, and polymorphically, typed functional logic language? This is the question we study in this paper. Logical features like nondeterminism and free variables cause interesting effects, which we examine based on examples and address by identifying appropriate conditions that guarantee standard free theorems or inequational versions thereof to hold. We see this case study as a stepping stone for a general theory, not provided here, involving the definition of a logical relation and other machinery required for parametricity arguments appropriate to functional logic languages."
  links:
    doi: "http://doi.acm.org/10.1145/1816027.1816035"
    dblp: "http://dblp.uni-trier.de/rec/bibtex/journals/sigplan/ChristiansenSV09"
    successor: "https://researchr.org/publication/CSV10"
  researchr: "https://researchr.org/publication/ChristiansenSV09"
  cites: 0
  citedby: 0
  journal: "SIGPLAN Notices"
  volume: "44"
  number: "11"
  pages: "7"
  kind: "article"
  key: "ChristiansenSV09"
- title: "Free theorems for functional logic programs"
  author:
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  - name: "Daniel Seidel"
    link: "http://wob.iai.uni-bonn.de/Wob/en/view/class217_id1454.html"
  - name: "Janis Voigtländer"
    link: "http://www.iai.uni-bonn.de/~jv/"
  year: "2010"
  doi: "http://doi.acm.org/10.1145/1707790.1707797"
  abstract: "Type-based reasoning is popular in functional programming. In particular, parametric polymorphism constrains functions in such a way that statements about their behavior can be derived without consulting function definitions. Is the same possible in a strongly, and polymorphically, typed functional logic language? This is the question we study in this paper. Logical features like nondeterminism and free variables cause interesting effects, which we examine based on examples and address by identifying appropriate conditions that guarantee standard free theorems or inequational versions thereof to hold. We see this case study as a stepping stone for a general theory, not provided here, involving the definition of a logical relation and other machinery required for parametricity arguments appropriate to functional logic languages."
  links:
    doi: "http://doi.acm.org/10.1145/1707790.1707797"
  tags:
  - "programming languages"
  - "rule-based"
  - "case study"
  - "functional programming"
  - " Curry"
  - "Haskell"
  - "relational parametricity"
  - "logic programming"
  - "programming"
  - "logic"
  - "type theory"
  researchr: "https://researchr.org/publication/CSV10"
  cites: 0
  citedby: 0
  pages: "39-48"
  booktitle: "Proceedings of the 4th ACM Workshop Programming Languages meets Program Verification, PLPV 2010, Madrid, Spain, January 19, 2010"
  editor:
  - name: "Cormac Flanagan"
    link: "https://researchr.org/alias/cormac-flanagan"
  - name: "Jean-Christophe Filliâtre"
    link: "https://researchr.org/alias/jean-christophe-filli%C3%A2tre"
  publisher: "ACM"
  isbn: "978-1-60558-890-2"
  kind: "inproceedings"
  key: "CSV10"
- title: "Denotation by Transformation"
  author:
  - name: "Bernd Braßel"
    link: "http://www.informatik.uni-kiel.de/prog/mitarbeiter/bernd-brassel/"
  - name: "Jan Christiansen"
    link: "http://korsika.informatik.uni-kiel.de/~jac/wordpress/"
  year: "2007"
  doi: "http://dx.doi.org/10.1007/978-3-540-78769-3_7"
  links:
    doi: "http://dx.doi.org/10.1007/978-3-540-78769-3_7"
  tags:
  - "transformation"
  researchr: "https://researchr.org/publication/BrasselC07"
  cites: 0
  citedby: 0
  pages: "90-105"
  booktitle: "Logic-Based Program Synthesis and Transformation, 17th International Symposium, LOPSTR 2007, Kongens Lyngby, Denmark, August 23-24, 2007, Revised Selected Papers"
  editor:
  - name: "Andy King"
    link: "https://researchr.org/alias/andy-king"
  volume: "4915"
  series: "Lecture Notes in Computer Science"
  publisher: "Springer"
  isbn: "978-3-540-78768-6"
  kind: "inproceedings"
  key: "BrasselC07"