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SUMMARY:Group actions on C*-algebras and obstruction theory - Masaki  Izum
 i (Kyoto University)
DTSTART:20170620T150000Z
DTEND:20170620T160000Z
UID:TALK73102@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:<span>This talk gives an account of the roles in group actions
  on C*-algebras played by the classical obstruction theory for fiber bundl
 es. More specifically\, I discuss the following deciding problems: <br> <b
 r> (1) whether a given 2-cocycle action is equivalent to an ordinary actio
 n or not\, <br> (2) whether a given 1-cocycle of an action is an (asymptot
 ic) coboundary or not\,<br> (3) whether two given actions are cocycle conj
 ugate or not.<br> <br> The idea works well for poly-Z groups on Kirchberg 
 algebras.<br> <br> This is joint work with Hiroki Matui. </span><br><br><b
 r>
LOCATION:Seminar Room 2\, Newton Institute
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