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Ideal structure and state spaces of operator algebras

In Chapter 0, we give a brief discussion of positive linear functionals on C<sup>*</sup>-algebras. We discuss the relation between states and representations of C<sup>*</sup>-algebras in section 0.1. Some properties of factorial states and primal ideals of C<sup>*</sup>-algebras are considered in section 0.2. In Chapter 1, we determine the primal ideals in certain C<sup>*</sup>-algebras. We study an antiliminal C<sup>*</sup>-algebra considered by Vesterstro m [38] in section 1.1. A variant of a nonliminal postliminal C<sup>*</sup>-algebra constructed by Kadison, Lance and Ringrose ([18] and [3]) is considered in section 1.2. Also, we study in section 1.3 a liminal C<sup>*</sup>-algebra constructed by J. Dixmier [10]. Chapter 2 is concerned with tensor products and primal ideals of C<sup>*</sup>-algebras. In Chapter 3, we try to answer the following question 'when can the pure state space overlineP(A) be written as a union of weak<sup>*</sup>-closed simplicial faces of the quasi state space Q(A)?' In section 3.1, we define a condition which we call (*), in terms of equivalent pure states, and we prove that it is equivalent to the pure state space overlineP(A) being a union of weak<sup>*</sup>-closed simplicial faces of the state space S(A), where A is a unital C<sup>*</sup>-algebra. We prove that the latter condition is equivalent to the pure state space overlineP(A) being a union of weak<sup>*</sup>-closed simplicial faces of the quasi state space Q(A). In section 3.2, we consider questions of stability for the condition (*). Some C<sup>*</sup>-algebras whose irreducible representations are of finite dimension are studied in section 3.3. Their pure state spaces are determined, thus giving examples and counter examples in connection with condition (*). Finally, in section 3.4, we prove that the factorial state space overlineF(A) is a union of weak<sup>*</sup>-closed simplicial faces of Q(A) if, and only if, A is abelian.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:381909
Date January 1987
CreatorsZaki, Adel Mohamed
PublisherUniversity of Aberdeen
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU498573

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