BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Gabor Elek (Lancaster) DTSTART:20210521T130000Z DTEND:20210521T140000Z DTSTAMP:20260423T021104Z UID:WCS/27 DESCRIPTION:Title: Uni form amenability\nby Gabor Elek (Lancaster) as part of Warwick Combina torics Seminar\n\n\nAbstract\nAccording to the classical result of Connes\ , Feldman and Weiss\, measured hyperfiniteness of a group action is equiva lent to measured amenability. In the Borel category it is known that hype rfiniteness implies amenability and it is conjectured that the converse is true. Based on the work of Anantharaman-Delaroche and Renault\, one can i ntroduce the notion of uniform amenability\, a strengthening of measured a menability (it is a sort of exactness in the category of measurable action s\, so the famous Gromov-Osajda groups have no free uniformly amenable act ions). One can also introduce the notion of uniform hyperfiniteness in a r ather natural way. We prove that the two notions are equivalent provided t hat the measurable action satisfies a boundedness condition for the Radon- Nikodym derivative (e.g. in the case of Poisson boundaries).\n LOCATION:https://researchseminars.org/talk/WCS/27/ END:VEVENT END:VCALENDAR