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SUMMARY:Rothschild Lecture: Classification of von Neumann algebras - Stefa
 an Vaes (KU Leuven)
DTSTART:20170612T150000Z
DTEND:20170612T160000Z
UID:TALK72890@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:The theme of this talk is the dichotomy between amenability an
 d non-amenability. Because the group of motions of the three-dimensional E
 uclidean space is non-amenable (as a group with the discrete topology)\, w
 e have the Banach-Tarski paradox. In dimension two\, the group of motions 
 is amenable and there is therefore no paradoxical decomposition of the dis
 k. This dichotomy is most apparent in the theory of von Neumann algebras: 
 the amenable ones are completely classified by the work of Connes and Haag
 erup\, while the non-amenable ones give rise to amazing rigidity theorems\
 , especially within Sorin Popa&#39\;s deformation/rigidity theory. I will 
 illustrate the gap between amenability and non-amenability for von Neumann
  algebras associated with countable groups\, with locally compact groups\,
  and with group actions on probability spaces.<br><br>
LOCATION:Seminar Room 1\, Newton Institute
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