Universiteit Leiden

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Crossed product algebras associated with topological dynamical systems

Promotor: S.M. Verduyn Lunel, Co-promotoren: M.F.E. de Jeu, S.D. Silvestrov

Christian Svensson
25 maart 2009
Thesis in Leiden Repository

We study connections between topological dynamical systems and associated algebras of crossed product type. We derive equivalences between structural properties of a crossed product and dynamical properties of the associated system and furthermore derive qualitative results concerning the crossed product that are true regardless of the corresponding dynamical system. The systems principally investigated are pairs of a compact Hausdorff space and a homeomorphism, where the integers act on former via iterations of the latter. With such a system a crossed product C*-algebra can be associated. We do not only focus on the C*-crossed product of a system, but also on a Banach *-algebra and a non-complete *-algebra that can both be embedded by *-isomorphisms as dense subalgebras of the C*-algebra; the C*-crossed product is the so-called enveloping C*-algebra of this Banach *-algebra. While investigations of the connections between a system and its C*-algebra have an extensive history, considerations of the other two algebras are new. For these algebras, we derive analogues of results from the case of C*-algebras, but also prove a theorem whose counterpart in the C*-algebra case is false. Furthermore we study the interplay between crossed products of Banach algebras by the integers and naturally associated systems.