Modules over the affine-Virasoro algebra of Nappi-Witten type.

In this paper, we determine a class of modules over the affine-Virasoro algebra of Nappi-Witten type, which are free of rank one when restricted to the subalgebra U (C L 0 ⊕ C d 0). We study when such modules are simple and determine the isomorphism classes. As a by-product, we obtain a class of indecomposable modules for the affine Nappi-Witten algebra. We also consider the tensor product of finitely many rank one free simple modules with an arbitrary simple restricted module. The simplicity and isomorphism classes are investigated. [ABSTRACT FROM AUTHOR]