Eusebio Gardella: Rokhlin actions of the circle on Kirchberg algebras. Oberseminar C*-Algebren.
Tuesday, 11.06.2013 15:15 im Raum N2
The Rokhlin property for actions of compact groups on C*-algebras was
introduced by Ilan Hirshberg and Wilhelm Winter, and is a
noncommutative analog of freeness for actions on compact spaces. The
definition for finite group actions has been around for much longer,
and finite group actions with the Rokhlin property are more or less
well understood by now. On the other hand, very little is known about
the Rokhlin property for compact, non-finite, group actions.
This talk will focus on the Rokhlin property for circle actions. We
will introduce the definition, present basic properties and construct
some examples. We will show that Kirchberg algebras are preserved
under formation of crossed products by such actions. The main result
of the talk is that circle actions with the Rokhlin property on
Kirchberg algebras are classified up to conjugacy by their equivariant
K-theory.
We will then specialize to circle actions on the Cuntz algebra
\mathcal{O}_2. In this case, it will be shown that circle actions with
the Rokhlin property are generic, that any two of them are conjugate,
and that the restriction to any finite subgroup of the circle again
has the Rokhlin property (in general they have Rokhlin dimension one).
Angelegt am Friday, 07.06.2013 08:46 von Elke Enning
Geändert am Friday, 07.06.2013 10:29 von Elke Enning
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