Organizers: Francesca Arici (Leiden University), Joakim Arnlind (Linköping University), Sven Raum (Stockholm University/University of Potsdam), Koen van den Dungen (University of Bonn)

In the first two weeks of May 2023, the NSeaG2023 meeting took place at the Hausdorff Center for Mathematics in Bonn. It continued the series NSeaG — Noncommutative Geometry along the North Sea — started in spring 2022 at the Lorentz Center. The event consisted of a Hausdorff School followed by a Workshop on “Noncommutative Geometry and Operator Algebras”.

Noncommutative Geometry (NCG) is a broad area of mathematics connected to a variety of topics, which can be a challenging situation for early career researchers in the field. The Hausdorff School addressed this need and introduced participants to a selection of active research topics through mini-courses, notably on unbounded KK-theory and spectral triples, the Baum–Connes conjecture, quantum groups, and quantum metric spaces. An in-depth introduction, leading up to state-of-the-art knowledge in these lines of research was provided.

The NSeaG2023 Workshop provided a platform for the exchange of new ideas and discussion of recent developments for researchers in noncommutative geometry (NCG) and neighbouring topics. Its geographic focus on activities along the North Sea supports community building in this area.


  • Bram Mesland (Leiden University): Unbounded KK-theory & Spectral triples (lecture notes)
  • Nigel Higson (Penn State University): Baum–Connes conjecture
  • Christian Voigt (University of Glasglow): Quantum groups (lecture notes)
  • Frédéric Latrémolière (University of Denver): Quantum metric spaces (lecture notes)