Vogan Diagrams of Real Forms of Affine Kac–Moody Lie Algebras

A Vogan diagram is actually a Dynkin diagram with some additional structure. This paper develops theory of Vogan diagrams for “almost compact” real forms of indecomposable nontwisted affine Kac–Moody Lie algebras. Here, the equivalence classes of Vogan diagrams are in one–one correspondence with the isomorphism classes of almost compact real forms.