Tuesday, September 30, 2025

Autumn 2025


3 October

Viska Arbogast

Numbers as Equations

Video. Click, use Passcode: M9ibFN?3

Sunday, September 7, 2025

Autumn 2025

 

From Wikipedia


11, 18, 25  Sep 2025

Jerzy Kocik

Coxeter groups, and an unconventional view on the unimodular group (with pictures)



Part 1:  Coxeter groups (the idea)

Part 2:  Modular group as a Coxeter group

Part 3:  "Supermodular" group and an unexpected application 


For part 1, you may consult a nicely written text by J. Baez:  Coxeter and Dynkin diagrams