University of Sydney Algebra Seminar

John Graham

Friday 23 February, 12-1pm, Place: Carslaw 375

Some Reflections on Root Systems

Crystallographic finite and affine root systems are normally studied for their applications to Lie theory. To entertain myself while I was learning some programming, I built a module to calculate with them following Bourbaki and Macdonald. In the talk I present some observations from this perspective that don’t seem to have made it to the textbooks. The themes are (1) concrete constructions; (2) the ignored non-reduced case; and (3) folding and twisting.