Twisted $\Gamma$-Lie algebras and their vertex operator representations

Abstract

Let $\Gamma$ be a generic subgroup of the multiplicative group ${\mathbb{C}}^{\ast }$ of nonzero complex numbers. We define a class of Lie algebras associated to $\Gamma$, called twisted $\Gamma$-Lie algebras, which is a natural generalization of the twisted affine Lie algebras. Starting from an arbitrary even sublattice $Q$ of ${\mathbb{Z}}^N$ and an arbitrary finite order isometry of ${\mathbb{Z}}^N$ preserving $Q$, we construct a family of twisted $\Gamma$-vertex operators acting on generalized Fock spaces which afford irreducible representations for certain twisted $\Gamma$-Lie algebras. As application, this recovers a number of known vertex operator realizations for infinite dimensional Lie algebras, such as twisted affine Lie algebras, extended affine Lie algebras of type $A$, trigonometric Lie algebras of series $A$ and $B$, unitary Lie algebras, and $BC$-graded Lie algebras.