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arXiv · 1610.09276

Boundary amenability of groups via ultrapowers

Stephen Avsec·Isaac Goldbring
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Abstract

We use $\mathrm{C}^{\ast}$-algebra ultrapowers to give a new construction of the Stone-Cech compactification of a separable, locally compact space. We use this construction to give a new proof of the fact that groups that act isometrically, properly, and transitively on trees are boundary amenable.

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Stephen Avsec, Isaac Goldbring. 2016-10-28. Boundary amenability of groups via ultrapowers. https://arxiv.org/abs/1610.09276

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