• Title/Summary/Keyword: C*-algebra

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FREE PROBABILITY THEORY AND ITS APPLICATION

  • Heo, Jaeseong
    • Journal of the Chungcheong Mathematical Society
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    • v.15 no.2
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    • pp.13-23
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    • 2003
  • We prove a simplicity of the $C^*$-algebra generated by some $C^*$-subalgebra and a Haar unitary in a free product of finite von Neumann algebras. Some examples and questions are given.

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Homotopy of projections in C^*-algebras

  • Kim, Sang-Og
    • Communications of the Korean Mathematical Society
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    • v.12 no.1
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    • pp.75-78
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    • 1997
  • We show that if a simple $C^*$-algebra A satisfies certain $K_1$-group conditions, then two unitarily equivalent projections are homotopic. Also we show that the equivalence of projections determined by a dimension function is a homotopy.

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REDUCED CROSSED PRODUCTS BY SEMIGROUPS OF AUTOMORPHISMS

  • Jang, Sun-Young
    • Journal of the Korean Mathematical Society
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    • v.36 no.1
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    • pp.97-107
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    • 1999
  • Given a C-dynamical system (A, G, $\alpha$) with a locally compact group G, two kinds of C-algebras are made from it, called the full C-crossed product and the reduced C-crossed product. In this paper, we extend the theory of the classical C-crossed product to the C-dynamical system (A, G, $\alpha$) with a left-cancellative semigroup M with unit. We construct a new C-algebra A $\alpha$rM, the reduced crossed product of A by the semigroup M under the action $\alpha$ and investigate some properties of A $\alpha$rM.

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K-THEORY OF CROSSED PRODUCTS OF C*-ALGEBRAS

  • SUDO TAKAHIRO
    • The Pure and Applied Mathematics
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    • v.12 no.1
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    • pp.1-15
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    • 2005
  • We study continuous fields and K-groups of crossed products of C*-algebras. It is shown under a reasonable assumption that there exist continuous fields of C* -algebras between crossed products of C* -algebras by amenable locally compact groups and tensor products of C* -algebras with their group C* -algebras, and their K-groups are the same under the additional assumptions.

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MORITA EQUIVALENCE FOR NONCOMMUTATIVE TORI

  • Park, Chun-Gil
    • Bulletin of the Korean Mathematical Society
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    • v.37 no.2
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    • pp.249-254
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    • 2000
  • We give an easy proof of the fact that every noncommutative torus $A_{\omega}$ is stably isomorphic to the noncommutative torus $C(\widehat{S\omega}){\;}\bigotimes{\;}A_p$ which hasa trivial bundle structure. It is well known that stable isomorphism of two separable $C^{*}-algebras$ is equibalent to the existence of eqivalence bimodule between the two stably isomorphic $C^{*}-algebras{\;}A_{\omega}$ and $C(\widehat{S\omega}){\;}\bigotimes{\;}A_p$.

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THE WOVEN FRAME OF MULTIPLIERS IN HILBERT C* -MODULES

  • Irani, Mona Naroei;Nazari, Akbar
    • Communications of the Korean Mathematical Society
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    • v.36 no.2
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    • pp.257-266
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    • 2021
  • In this paper, by using the sequence of adjointable operators from C*-algebra 𝓐 into Hilbert 𝓐-module E, the woven frames of multipliers in Hilbert C*-modules are introduced. Meanwhile, we study the effect of operators on these frames and, also we construct the new woven frame of multipliers in Hilbert 𝓐-module 𝓐. Finally, compositions of woven frames of multipliers in Hilbert C*-modules are studied.