Mathematische Zeitschrift

, Volume 245, Issue 4, pp 761–779 | Cite as

Spectral properties of operator logarithms

Article

Abstract.

We prove that the spectral height of the logarithm log A of a sectorial operator A equals the spectral angle of A. This yields old results of Prüss/Sohr and McIntosh as corollaries. Then we construct a sectorial operator A on a UMD space having bounded imaginary powers such that the group type of (Ais)s∈ℝ is strictly greater than π.

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© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  1. 1.Abt. Angewandte AnalysisUniversität UlmUlm

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