- International:
Member of Academia Europaea.
Member of the Board of Directors of TARK (Theoretical Aspects of Rationality and Knowledge).
Member of the advisory committee of the Computing Research Repository (CoRR).
Editorial Advisor of the Theory and Practice of Logic Programming (TPLP) .
Founder and the first Editor-in-Chief of the ACM Transactions on Computational Logic (TOCL) .
Area editor of the Journal of Logic and Computation (JLC) .
One of the initiators of the Lipski Award.

- National:
Member of Dutch Association for Theoretical Computer Science (NVTI).
This page is maintained by Krzysztof R. Apt