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Crossed Products by Semigroups of Endomorphisms and Groups of Partial Automorphisms

Published online by Cambridge University Press:  20 November 2018

Nadia S. Larsen*
Affiliation:
Department of Mathematics, Institute for Mathematical Sciences, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark, e-mail: nadia@math.ku.dk
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Abstract

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We consider a class $(A,\,S,\,\alpha )$ of dynamical systems, where $S$ is an Ore semigroup and $\alpha$ is an action such that each ${{\alpha }_{s}}$ is injective and extendible (i.e. it extends to a non-unital endomorphism of the multiplier algebra), and has range an ideal of $A$. We show that there is a partial action on the fixed-point algebra under the canonical coaction of the enveloping group $G$ of $S$ constructed in [15, Proposition 6.1]. It turns out that the full crossed product by this coaction is isomorphic to $A\,{{\rtimes }_{\alpha }}\,S$. If the coaction is moreover normal, then the isomorphism can be extended to include the reduced crossed product. We look then at invariant ideals and finally, at examples of systems where our results apply.

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2003

References

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