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Bimodule coefficients, Riesz transforms on Coxeter groups and strong solidity.
- Source :
- Groups, Geometry & Dynamics; 2024, Vol. 18 Issue 2, p501-549, 49p
- Publication Year :
- 2024
-
Abstract
- In deformation-rigidity theory, it is often important to know whether certain bimodules are weakly contained in the coarse bimodule. Consider a bimodule H over the group algebra C[Γ] with Γ a discrete group. The starting point of this paper is that if a dense set of the so-called coefficients of H is contained in the Schatten S<subscript>p</subscript> class p ∈ [2,∞), then the n-fold tensor power H<subscript>Γ</subscript><superscript>⊗n</superscript> for n ≥ p/2 is quasi-contained in the coarse bimodule. We apply this to gradient bimodules associated with the carré du champ of a symmetric quantum Markov semi-group. For Coxeter groups, we give a number of characterizations of having coefficients in S<subscript>p</subscript> for the gradient bimodule constructed from the word length function. We get equivalence of: (1) the gradient-S<subscript>p</subscript> property introduced by the second named author, (2) smallness at infinity of a natural compactification of the Coxeter group, and for a large class of Coxeter groups, (3) walks in the Coxeter diagram called parity paths. We derive several strong solidity results. In particular, we extend current strong solidity results for right-angled Hecke von Neumann algebras beyond right-angled Coxeter groups that are small at infinity. Our general methods also yield a concise proof of a result by Sinclair for discrete groups admitting a proper cocycle into a p-integrable representation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 16617207
- Volume :
- 18
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Groups, Geometry & Dynamics
- Publication Type :
- Academic Journal
- Accession number :
- 176788146
- Full Text :
- https://doi.org/10.4171/GGD/752