Vogan diagram

Summary

A Vogan diagram is a Dynkin diagram with extra marks that records a real form of a complex semisimple Lie algebra. The marks come from a Cartan involution acting on the roots of a maximally compact Cartan subalgebra. Vogan diagrams give a short route to the classification of real simple Lie algebras. They play the role for compact Cartan subalgebras that Satake diagrams play for maximally split ones.