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The similarity problem for cyclic homomorphisms on a C*-algebra

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Similarity Problems and Completely Bounded Maps

Part of the book series: Lecture Notes in Mathematics ((LNM,volume 1618))

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Summary

In this chapter, we first study inequalities satisfied by any bounded linear operator u: A→Y on a C*-algebra with values in a Banach space Y. The case when Y is another C*-algebra is of particular interest. Then we turn to homomorphisms u: A →* B(H) and prove that, if u is cyclic (= has a cyclic vector), boundedness implies complete boundedness. Hence bounded cyclic homomorphisms are similar to *-representations. This extends to homomorphisms with finite cyclic sets. We also include the positive solution to the similarity problem for C*-algebras without tracial states and for nuclear C*-algebras. Finally, we show that for a given C*-algebra, the similarity problem and the derivation problem are equivalent.

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Notes and Remarks on Chapter 7

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© 1996 Springer-Verlag Berlin Heidelberg

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Pisier, G. (1996). The similarity problem for cyclic homomorphisms on a C*-algebra. In: Similarity Problems and Completely Bounded Maps. Lecture Notes in Mathematics, vol 1618. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-21537-1_8

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  • DOI: https://doi.org/10.1007/978-3-662-21537-1_8

  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-60322-1

  • Online ISBN: 978-3-662-21537-1

  • eBook Packages: Springer Book Archive

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