Expansions of the real field by discrete subgroups of Gl$_n(\mathbb{C})$

Abstract

Let $\Gamma$ be an infinite discrete subgroup of Gl$_n(\mathbb{C})$. Then either $(\mathbb{R}, <, +, \cdot, \Gamma)$ is interdefinable with $(\mathbb{R}, <, +, \cdot, \lambda^\mathbb{Z})$ for some $\lambda \in \mathbb{R}$, or $(\mathbb{R}, < , +, \cdot, \Gamma)$ defines the set of integers. When $\Gamma$ is not virtually abelian, the second case holds.