BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Martijn Caspers (TU Delft\, Netherlands) DTSTART:20201207T150000Z DTEND:20201207T160000Z DTSTAMP:20260422T175221Z UID:QGS/5 DESCRIPTION:Title: Ries z transforms on compact quantum groups and strong solidity\nby Martijn Caspers (TU Delft\, Netherlands) as part of Quantum Groups Seminar [QGS]\ n\n\nAbstract\nThe Riesz transform is one of the most important and classi cal examples of a Fourier multiplier on the real numbers. It may be descri bed as the operator $\\nabla_j \\Delta^{-1/2}$ where $\\nabla_j = d/dx_j$ is the derivative and $\\Delta$ is the Laplace operator. In a more general context the Riesz transform may always be defined for any diffusion semig roup on the reals. In case the generator of this semi-group is the Laplace operator the classical Riesz transform is retrieved. In quantum probabili ty the quantum Markov semi-groups play the role of the diffusion semi-grou ps and again a suitable notion of Riesz transform can be described.\n\nWe show that the Riesz transform may be used to prove rigidity properties of von Neumann algebras. We focus in particular on examples from compact quan tum groups. Using these tools we show that a class of quantum groups admit s rigidity properties. The class has the following properties:\n\n(1) $\\t ext{SU}_q(2)$ is contained in it.\n\n(2) The class is stable under monoida l equivalence\, free products\, dual quantum subgroups and wreath products with $S^+_N$.\n\nThe rigidity properties include the Akemann-Ostrand prop erty and strong solidity. Part of this talk is based on joint work with Ma teusz Wasilewski and Yusuke Isono.\n LOCATION:https://researchseminars.org/talk/QGS/5/ END:VEVENT END:VCALENDAR