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Groups with the Haagerup Property Volume 31 || Open Questions and Partial Results

✍ Scribed by Cherix, Pierre-Alain; Jolissaint, Paul; Valette, Alain; Cowling, Michael; Julg, Pierre


Book ID
115317014
Publisher
Birkhäuser Basel
Year
2001
Tongue
English
Weight
1016 KB
Edition
1
Category
Article
ISBN
3034882378

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✦ Synopsis


A locally compact group has the Haagerup property, or is a-T-menable in the sense of Gromov, if it admits a proper isometric action on some affine Hilbert space. As Gromov's pun is trying to indicate, this definition is designed as a strong negation to Kazhdan's property (T), characterized by the fact that every isometric action on some affine Hilbert space has a fixed point. The aim of this book is to cover, for the first time in book form, various aspects of the Haagerup property. New characterizations are brought in, using ergodic theory or operator algebras. Several new examples are given, and new approaches to previously known examples are proposed. Connected Lie groups with the Haagerup property are completely characterized.