News

Fall 2025: My group's new seminar webpage is up.

March 2-March 20, 2026: Bernoulli programme on algebraic aspects of metric and integral geometry. We welcome applications for the school (March 9-13) and registrations for the converence (March 16-20).

3 November 2025: Schläfli lecture by Kathlén Kohn.

Teaching

Discrete Mathematics

• Thursday 14 February: I included an exercise on Möbius transformations. See this patch. A nice movie about these transformations can be found here.
• Thursday 31 January: some of the material in Chapter 1 of the notes refers to knowledge about graph embeddability (Section 3.3) that you will only learn in a few weeks in the course Optimization in networks (last year my part of the course was later relative to this course). I will skip these parts, proceed with some material from later chapters, and get back to this material later. You can download a patch where a short section on Desargues is inserted, and the exposition of the section on simple connectedness has been improved.
• I found a very funny lecture on the history of design theory, a bit of which we will see through projective spaces. It can be found here.
• A lot on design theory (more serious stuff) can be found here.