Prof. Dr.habil. Dipl.-Ing. Thom Frühwirth

Institute of Software Engineering and Programming Languages
Faculty of Engineering, Computer Science and Psychology
Ulm University
89069 Ulm, Germany


Research Interests

The Craft of Reasoning and The Art of Programming

Computational logic, Rule-based programming, Constraint logic programming, Program analysis, Constraint reasoning.

Curriculum Vitae

Thom Frühwirth is the developer of the programming language and formalism Constraint Handling Rules (CHR) and author of the eponymous book. He has (co-)authored five books on constraint programming and reasoning, including a leading textbook. He is also known for his work in type theory and spatio-temporal reasoning. He is among the top researchers in Computational Logic and is the editor of 11 books in this area. He has published over 200 research papers with over 5000 citations. He has served on over 100 program committees and given over 100 invited talks. He has been involved in 15 publicly funded research projects.

Thom Frühwirth teaches and publishes since 1984. He obtained his Ph.D. in Computer Science at the Technical University of Vienna in 1990, after visiting the State University of New York at Stony Brook with a one-year Fulbright grant and invitations to the Weizmann Institute of Science in Rehovot. From 1991 he was researcher at the European Computer Industry Research Centre in Munich. In 1996 he joined the Ludwig Maximilians University in Munich. There he became assistant professor in 1998 after his habilitation and held visiting positions at the universities of Pisa, Monash Melbourne, PUC Rio de Janeiro, and the CWI research center in Amsterdam. In 2002 he was appointed professor at Ulm University, Germany, and entered into collaboration with the German University in Cairo. He served on the examination board for Computer Science for 17 years, the PhD committee for 15 years, on the examination board for Cognitive Systems, and on the habilitation committee. [Full CV up to 2005].

Major Book Publications

Constraint Handling Rules

CHR - Compilation,
Execution, Analysis

Essentials of
Constraint Programming


The Computer Art of
Mason's Mark Design

Recent Book Editorships

Robert Kowalski: Logic for Problem Solving, Revisited
Kowalski: Logic for
Problem Solving, Revisited
Edward Tsang: Foundations of Constraint Satisfaction
Tsang: Foundations of
Constraint Satisfaction
Daniel Gall: Analysis of Cognitive Models in Constraint Handling Rules
Gall: Analysis of Cognitive
Models in CHR
Jan-Hendrik Lorenz: Restart Strategies
Lorenz: Restart Strategies
Hariolf Betz: A Unified Analytical Foundation for Constraint Handling Rules
Betz: A Unified Analytical
Foundation for CHR

SWI Prolog
Reference Manual

SICStus Prolog
User's Manual

What's New?

- New Paper: Runtime Repeated Recursion Unfolding in CHR: A Just-In-Time Online Program Optimization Stratagey That Can Achieve Super-Linear Speedup, January 2024.
- Program committee member of the 8th International Joint Conference on Rules and Reasoning (RuleML+RR 2024), Bucharest, Romania, September 2024.
- New Paper: FreeCHR: An Algebraic Framework for CHR-Embeddings, June 2023.

Archived News

Online Tools, Demos and Talk

- Online Interactive Constraint Handling Rules Prolog Programming Demo Tool (replacing WebCHR)
- chrjs: Online Interactive Constraint Handling Rules (CHR) Demo Tool and JavaScript JIT CHR Compiler
- Constraint Handling Rules (CHR) bibliography and blog
- Vortrag Computer knacken harte Nüsse - Von Sudoku über den Aktienhandel zum Robotersegeln, Video of talk on CHR applications (in German with English slides), Thom Frühwirth.

Teaching since 1984

Currently teaching this semester

Topics for projects, Bachelor, Master and PhD theses

Recent Teaching in campusonline
Teaching since 2004 in campusonline
Teaching 1984 - 2005 listed in CV

Lecture Slides / Vorlesungsfolien

Constraint Programming
Rule-Based Programming
Logische Programmierung mit Prolog und CHR
Einführung in die Informatik mit Java


"The perfect crime is that of an unconditional realization of the world by the actu­alization of all data, the transformation of all our acts and all events into pure information: in short, the final solution, the resolution of the world ahead of time by the cloning of reality and the extermination of the real by its double."
The Perfect Crime, Jean Baudrillard, 1996

Thom Frühwirth, April 9, 2024. This page is part of a multi-frame html document.