### Abstract

Using topological entropy of automorphisms of C*-algebras, it is shown that some important facts from the theory of AF algebras do not carry over to the class of A algebras. It is shown that in general one cannot perturb a basic building block into a larger one which almost contains it. The same entropy obstruction used to prove this fact also provides a new obstruction to the known fact that two injective homomorphisms from a building block into an A algebra need not differ by an (inner) automorphism when they agree on K-theory.

Original language | English (US) |
---|---|

Pages (from-to) | 2603-2609 |

Number of pages | 7 |

Journal | Proceedings of the American Mathematical Society |

Volume | 128 |

Issue number | 9 |

State | Published - Dec 1 2000 |

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### All Science Journal Classification (ASJC) codes

- Mathematics(all)
- Applied Mathematics

### Cite this

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*Proceedings of the American Mathematical Society*, vol. 128, no. 9, pp. 2603-2609.

**Topological entropy, embeddings and unitaries in nuclear quasidiagonal c*-algebras.** / Brown, Nathanial P.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Topological entropy, embeddings and unitaries in nuclear quasidiagonal c*-algebras

AU - Brown, Nathanial P.

PY - 2000/12/1

Y1 - 2000/12/1

N2 - Using topological entropy of automorphisms of C*-algebras, it is shown that some important facts from the theory of AF algebras do not carry over to the class of A algebras. It is shown that in general one cannot perturb a basic building block into a larger one which almost contains it. The same entropy obstruction used to prove this fact also provides a new obstruction to the known fact that two injective homomorphisms from a building block into an A algebra need not differ by an (inner) automorphism when they agree on K-theory.

AB - Using topological entropy of automorphisms of C*-algebras, it is shown that some important facts from the theory of AF algebras do not carry over to the class of A algebras. It is shown that in general one cannot perturb a basic building block into a larger one which almost contains it. The same entropy obstruction used to prove this fact also provides a new obstruction to the known fact that two injective homomorphisms from a building block into an A algebra need not differ by an (inner) automorphism when they agree on K-theory.

UR - http://www.scopus.com/inward/record.url?scp=23044523706&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=23044523706&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:23044523706

VL - 128

SP - 2603

EP - 2609

JO - Proceedings of the American Mathematical Society

JF - Proceedings of the American Mathematical Society

SN - 0002-9939

IS - 9

ER -