[Settfa] Tuesday 22/09, <h3>Karen Strung</h3>

[kubis at math.cas.cz]

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 Tuesday 22nd September, 10:30am 
 
  Place: IM in konírna 

 
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 Speaker:Karen Strung
, IM CAS
 Title: C*-algebras and groupoids from minimal dynamical systems

 Abstract  

 This talk is based on joint work with Robin Deeley and Ian Putnam, where we study the existence of minimal dynamical systems, their orbit and minimal orbit-breaking equivalence relations, and their applications to C*-algebras and K-theory. In particular, we show that given any finite CW-complex there exists a space with the same K-theory and cohomology that admits a minimal homeomorphism. The proof relies on the existence of homeomorphisms on point-like spaces constructed by the authors in previous work, together with existence results for skew product systems due to Glasner and Weiss.


To any minimal dynamical system one can associate minimal equivalence relations by breaking orbits at small subsets. These were originally used by Putnam in his study of Cantor minimal systems, in which case they are so-called AF relations. Using Renault's groupoid C*-algebra construction we can associate K-theory groups to minimal dynamical systems and orbit-breaking equivalence relations. We show that given arbitrary countable abelian groups G_0 and G_1 we can find a minimal orbit-breaking relation such that the K-theory of the associated C*-algebra is exactly this pair.



These results have important applications to the Elliott classification program for C*-algebras. In particular, we make a step towards determining the range of the Elliott invariant of the C*-algebras associated to minimal dynamical systems and their minimal orbit-breaking relations.
 

 
Please note that the seminar starts at 10:30 (instead of the usual 10:00).


 For more information see the seminar web page at 
 https://calendar.math.cas.cz/set-theory-and-analysis-actual .