Subalgebras of Hyperbolic Kac-Moody Algebras

Alex J. Feingold, Hermann Nicolai

The hyperbolic (and more generally, Lorentzian) Kac-Moody (KM) Lie algebras $\cA$ of rank $r+2>2$ are shown to have a rich structure of indefinite KM subalgebras which can be des…