Poincaré inequalities and rigidity for actions on Banach spaces
Journal of the European Mathematical Society, Tome 17 (2015) no. 3, pp. 689-709
Cet article a éte moissonné depuis la source EMS Press
The aim of this paper is to extend the framework of the spectral method for proving property (T) to the class of reflexive Banach spaces and present a condition implying that every affine isometric action of a given group G on a reflexive Banach space X has a fixed point. This last property is a strong version of Kazhdan's property (T) and is equivalent to the fact that H1(G,π)=0 for every isometric representation π of G on X. The condition is expressed in terms of p-Poincar\'{e} constants and we provide examples of groups, which satisfy such conditions and for which H1(G,π) vanishes for every isometric representation π on an Lp space for some p>2. Our methods allow to estimate such a p explicitly and yield several interesting applications. In particular, we obtain quantitative estimates for vanishing of 1-cohomology with coefficients in uniformly bounded representations on a Hilbert space. We also give lower bounds on the conformal dimension of the boundary of a hyperbolic group in the Gromov density model.
Classification :
22-XX, 46-XX
Keywords: Poincaré inequality, Kazhdan’s property (T); affine isometric action
Keywords: Poincaré inequality, Kazhdan’s property (T); affine isometric action
@article{JEMS_2015_17_3_a6,
author = {Piotr W. Nowak},
title = {Poincar\'e inequalities and rigidity for actions on {Banach} spaces},
journal = {Journal of the European Mathematical Society},
pages = {689--709},
year = {2015},
volume = {17},
number = {3},
doi = {10.4171/jems/514},
url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/514/}
}
TY - JOUR AU - Piotr W. Nowak TI - Poincaré inequalities and rigidity for actions on Banach spaces JO - Journal of the European Mathematical Society PY - 2015 SP - 689 EP - 709 VL - 17 IS - 3 UR - http://geodesic.mathdoc.fr/articles/10.4171/jems/514/ DO - 10.4171/jems/514 ID - JEMS_2015_17_3_a6 ER -
Piotr W. Nowak. Poincaré inequalities and rigidity for actions on Banach spaces. Journal of the European Mathematical Society, Tome 17 (2015) no. 3, pp. 689-709. doi: 10.4171/jems/514
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