Abstract
Let A be a separable unital nuclear simple C*-algebra with torsion K 0(A), free K 1(A) and with the UCT. Let τ : A→M(\({\fancyscript K}\))/\({\fancyscript K}\) be a unital homomorphism. We prove that every unitary element in the commutant of τ (A) is an exponent, thus it is liftable. We also prove that each automorphism α on E with \( \ifmmode\expandafter\bar\else\expandafter\=\fi{\alpha } \in {\text{Aut}}_{0} {\left( A \right)} \) is approximately inner, where E is a unital essential extension of A by \({\fancyscript K}\) and \( \ifmmode\expandafter\bar\else\expandafter\=\fi{\alpha } \) is the automorphism on A induced by α.
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References
Lin, H.: On the classification of C*-algebras of real rank zero with zero K 1. J. Operator Theory, 35, 147–178 (1996)
Blackadar, B.: K-Theory for operator algebras, Springer-Verlag, New York, 1986
Lin, H., Su, H.: Classification of direct limits of generalized Toeplitz algebras. Pacific J. Math., 181, 89–140 (1997)
Lin, H.: An introduction to the classification of amenable C*-algebras, World Scientific, New Jersey, London, Singapore, Hong Kong, Bangalore, 2001
Brown, L. G.: The universal coefficient theorem for Ext and quasidiagonality, Operator algebras and group representations, Vol. I (Neptun, 1980), 60–64, Monogr. Stud. Math., 17, Pitman, Boston, MA, 1984
Arveson, W.: Notes on extensions of C*-algebras. Duke J. Math., (2) 44, 329–355 (1977)
Pedersen, G. K.: C*-algebras and Their Automorphism Groups, Academic Press, London, New York, San Francisco, 1979
Lin, H.: Lifting automorphisms. K-Theory, 16(2), 105–127 (1999)
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Fang, X.C., Liu, S.D. Lifting Unitary Elements with Application to Approximately Inner Automorphisms. Acta Math Sinica 23, 1745–1750 (2007). https://doi.org/10.1007/s10114-005-0924-7
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DOI: https://doi.org/10.1007/s10114-005-0924-7