About
I am an associate professor and member of
the Programming, Logic and Intelligent
Systems research group in
the Department
of People and Technology at Roskilde
University, Denmark.
My research is in Knowledge Representation and Reasoning, a subarea
of Artificial Intelligence that studies how an agent's knowledge can
be represented symbolically and subsequently manipulated through
reasoning algorithms. Among other things, my work is concerned with
reasoning about action and change, reasoning about beliefs,
planning, agent program verification, synthesis, and machine ethics.
The ß in
my last name is a German letter that is roughly pronounced like
"ss" (as in pass), and not to be confused with a "b" or the
Greek letter beta
(β). An
alternative spelling is "Classen".
Latest News
2026-07-14
I have co-authored a paper with Torben Braüner on a tableau system for epistemic first-order logic with standard names. The paper will be presented by Torben at ARQNL 2026 in Lisbon, Portugal, as part of FLoC 2026.
2026-05-15
I will attend IJCAI 2026 in Bremen, Germany in August, where I will present the paper I co-authored with Daxin Liu on the size complexity and decidability of first-order progression.
2025-09-23
Later this week I will attend TABLEAUX 2025 in Reykjavik, Iceland. I am presenting a paper co-authored with Torben Braüner on a tableau system for first-order logic with standard names.
[all news]
Recent Publications
Jens Claßen and Torben Braüner:
A Tableau System for First-Order Epistemic Logic with Standard Names.
Proceedings of the 6th International Workshop on Automated Reasoning in Quantified Non-Classical Logics (ARQNL 2026), 2026. To appear.
PDFBibTeX
Jens Claßen and Daxin Liu:
On the Size Complexity and Decidability of First-Order Progression.
Proceedings of the 35th International Joint Conference on Artificial Intelligence (IJCAI 2026), ijcai.org, 2026. To appear.
PDFBibTeX
Jens Claßen and Torben Braüner:
A Tableau System for First-Order Logic with Standard Names.
Proceedings of the 34th International Conference on Automatic Reasoning with Analytic Tableaux and Related Methods (TABLEAUX 2025), pages 22-38, Springer, 2025.
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[all publications]