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PRODID:-//Memento EPFL//
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SUMMARY:Measured Group Theory\, Percolation and Non-Amenability
DTSTART:20151001T171500
DTEND:20151001T181500
DTSTAMP:20260510T213540Z
UID:59ceec9cac08fa9f42f10d7d01dbe7287172f8f66a5837f5543cd52b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Damien Gaboriau (CNRS\, ENSL\, Université de Lyon)\nAmenabili
 ty for groups is a concept introduced by J. von Neumann in his seminal art
 icle (1929) tin connection with the so-called Banach-Tarski paradox. It is
  easily shown that the free group F on two generators is non-amenable. It 
 follows that the countable discrete groups containing F are non-amenable. 
 von Neumann's problem examines whether the converse holds true. In the 80'
 s Ol'shanskii showed that his Tarski monsters lead to counter-examples. Ho
 wever\, in order to extend certain results from groups containing F to any
  non-amenable countable group G\, it may be enough to know that G contains
  F in a more dynamical sense.\nNamely\,  it may be sufficient to find a 
  probability measure preserving free action of G whose orbits contain the 
 orbits of some free action of F.\nThe solution to this ``measurable von Ne
 umann's problem'' involves percolation theory on Cayley graphs\, measured 
 laminations by subgraphs and some invariants of dynamical systems. I will 
 present an introduction to this subject\, with some examples\,  pictures\
 , and movies. We may even take this opportunity to start a ping-pong game.
 ..
LOCATION:BI A0 448 https://plan.epfl.ch/?room==BI%20A0%20448
STATUS:CONFIRMED
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