Derivations and Invariant Forms of Jordan and Alternative Tori

Jordan and alternative tori are the coordinate algebras of extended affine Lie algebras of type A1 and A2. In this paper we show that the derivation algebra of a Jordan torus is a semidirect product of the ideal of inner derivations and the subalgebra of central derivations. In the course of proving this result, we investigate derivations of the more general class of division graded Jordan and alternative algebras. We also describe invariant forms of these algebras.

(The present version of 25 January 2002 replaces the original version of 11 April 2001)

(This paper has appeared in Trans. AMS 355 (2003), 1079 - 1108)


E. Neher <neher@uottawa.ca> Y. Yoshii <yoshii@math.ualberta.ca>