Krzysztof Rafal Apt

Also known as Krzysztof R. Apt, Krzysztof Rafał Apt

Krzysztof Rafal Apt is a Polish-born computer scientist who works on logic programming, constraint programming and game theory. Born in Katowice in 1949, he earned a PhD in mathematics in 1974 and held posts in the Netherlands, France and the United States before settling at CWI in Amsterdam. He helped design the Alma-0 language in 1997, founded ACM Transactions on Computational Logic in 2000, and wrote Principles of Constraint Programming, which Cambridge University Press published in 2003. Elected to Academia Europaea in 2006, he is a CWI Fellow, an emeritus professor at the University of Amsterdam and an affiliated professor at the University of Warsaw.

Now at: National Research Institute for Mathematics and Computer Science in the Netherlands, University of Amsterdam and University of Warsaw
Born: 1949
Badges: Wayfarer
Loyal
Pioneer

Years link to their sources.

Timeline

1974–1987

From Warsaw to Paris

Born in Katowice in 1949, he studies mathematics in Wrocław and earns a PhD in mathematics at the Institute of Mathematics of the Polish Academy of Sciences in Warsaw in 1974. He then holds a postdoc at the Catholic University of Nijmegen, an assistant professorship at Erasmus University Rotterdam from 1978, and a CNRS research post in Paris from 1981.
1987–1990

Blakemore Professor at Austin

From 1987 to 1990, he is the William B. Blakemore II Professor in the Department of Computer Sciences in Austin, Texas.
1991

Professor at Amsterdam

In 1991, he becomes a full professor at the Institute for Language, Logic and Computation of the University of Amsterdam. He has been a senior researcher at CWI in Amsterdam since 1987.
1997

The Alma-0 language

Alma-0 appears in 1997, designed at CWI by Apt with Marc Bezem, Jacob Brunekreef, Vincent Partington and Andrea Schaerf. The language extends Modula-2 with logic-programming features and backtracking, and it supports constraint programming.
2000

Founding ACM TOCL

He founds ACM Transactions on Computational Logic in 2000 and serves as its first Editor-in-Chief.
2003

Principles of Constraint Programming

Cambridge University Press publishes his book Principles of Constraint Programming in 2003, a 407-page text on the field.
2006

Academia Europaea membership

He is elected to Academia Europaea in 2006, in its Informatics section.
As of October 2026

CWI Fellow and emeritus professor

He is a CWI Fellow, associated with the Networks and Optimization group in Amsterdam, and an affiliated professor at the University of Warsaw. He has been professor emeritus at the University of Amsterdam since 2014. His 2026 article "Tony Hoare: his path to the ACM Turing Award" appears in Formal Aspects of Computing.