Amenability for unitary groups of C*-algebras

Vadim Alekseev; Max Schmidt; Andreas Thom

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arXiv · 2305.13181

Amenability for unitary groups of C*-algebras

Vadim Alekseev·Max Schmidt·Andreas Thom

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Abstract

In this note we state a conjecture that characterizes unital C*-algebras for which the unitary group is amenable as a topological group in the norm topology. We prove the conjecture for simple, separable, stably finite, unital, $\mathcal Z$-stable, UCT C*-algebras with torsionfree K_0 using the progress on the Elliott classification program for nuclear C*-algebras as well as Pestov's study of amenability of gauge groups. Based on work of Kirchberg, we provide a counterexample to a question of Ng, who proposed a different characterization in earlier work.

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Vadim Alekseev, Max Schmidt, Andreas Thom. 2023-05-22. Amenability for unitary groups of C*-algebras. https://arxiv.org/abs/2305.13181

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