Bulletin of the
Korean Mathematical Society BKMS

In this paper we give an introduction to the theory of universal central extensions of perfect Lie algebras. In particular, we will provide a model for the universal coverings of Lie tori and we show that automorphisms and derivations lift to the universal coverings. We also prove that the universal covering of a Lie $\Lambda$-torus of type $\Delta$ is again a Lie $\Lambda$-torus of type $\Delta$.

Keywords: root graded Lie algebras, extended affine Lie algebras and Lie tori

MSC numbers: 17B67