Coxeter and Dynkin Diagrams

Coxeter and Dynkin diagrams classify a wide variety of structures, most notably finite reflection groups, lattices having such groups as symmetries, compact simple Lie groups and complex simple Lie algebras. The simply laced or ‘ADE’ Dynkin diagrams also classify finite subgroups of SU(2) and quivers with finitely many indecomposable representations.

I’m talking about Coxeter and Dynkin diagrams now in my This Week’s Finds seminars. I started in Lecture 4, which you can see on video already, a...