Free subgroups in weighted Leavitt Path Algebras

Abstract

We study unit groups of weighted Leavitt path algebras. Let $K$ be a field of characteristic $0$ and let $(E,ω)$ be a finite connected weighted graph. We prove that $L_K(E,ω)^\times$ is abelian if and only if $L_K(E,ω)$ is a domain. Equivalently, $L_K(E,ω)^\times$ contains no non-cyclic free subgroup if and only if $L_K(E,ω)$ is a domain.