Representation spaces for central extensions and almost commuting unitary matrices

Alejandro Adem, Man Chuen Cheng

Let $\Gamma$ denote a central extension of the form $1\to {\mathbb{Z}}^r\to \Gamma \to {\mathbb{Z}}^n\to 1$. In this paper we describe the topology of the spaces of homomorphisms $\text{Hom}(Γ, U(…