Rationality of the vertex algebra when is a nondegenerate even lattice of arbitrary rank
arXiv:0807.3897
Abstract
In this paper we prove that the vertex algebra is rational if is a negative definite even lattice of finite rank, or if is a non-degenerate even lattice of a finite rank that is neither positive definite nor negative definite. In particular, for such even lattices , we show that the Zhu algebras of the vertex algebras are semisimple. This extends the result of Abe which establishes the rationality of when is a positive definite even lattice of finite rank.