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arXiv · 1703.08907

HNN extensions of quasi-lattice ordered groups and their operator algebras

Astrid an Huef·Iain Raeburn·Ilija Tolich
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Abstract

The Baumslag-Solitar group is an example of an HNN extension. Spielberg showed that it has a natural positive cone, and that it is then a quasi-lattice ordered group in the sense of Nica. We give conditions for an HNN extension of a quasi-lattice ordered group $(G,P)$ to be quasi-lattice ordered. In that case, if $(G,P)$ is amenable as a quasi-lattice ordered group, then so is the HNN extension.

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Astrid an Huef, Iain Raeburn, Ilija Tolich. 2017-03-27. HNN extensions of quasi-lattice ordered groups and their operator algebras. https://arxiv.org/abs/1703.08907

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