# Proper proximality in non-positive curvature

@article{Horbez2020ProperPI, title={Proper proximality in non-positive curvature}, author={Camille Horbez and Jingyin Huang and Jean L'ecureux}, journal={arXiv: Group Theory}, year={2020} }

Proper proximality of a countable group is a notion that was introduced by Boutonnet, Ioana and Peterson as a tool to study rigidity properties of certain von Neumann algebras associated to groups or ergodic group actions. In the present paper, we establish the proper proximality of many groups acting on nonpositively curved spaces.
First, these include many countable groups $G$ acting properly nonelementarily by isometries on a proper $\mathrm{CAT}(0)$ space $X$. More precisely, proper…

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