Poincaré type inequalities for group measure spaces and related transportation cost inequalities
arXiv:1306.6099
Abstract
Let be a countable discrete group with an orthogonal representation on a real Hilbert space . We prove Poincaré inequalities for the group measure space , where both the group action and the Gaussian measure space are associated with the representation . The idea of proof comes from Pisier's method on the boundedness of Riesz transform and Lust-Piquard's work on spin systems. Then we deduce a transportation type inequality from the Poincaré inequalities in the general noncommutative setting. This inequality is sharp up to a constant (in the Gaussian setting). Several applications are given, including Wiener/Rademacher chaos estimation and new examples of Rieffel's compact quantum metric spaces.
28 pages; revised