Ukrainian Mathematical Journal

, Volume 58, Issue 10, pp 1512–1516 | Cite as

On estimate for numerical radius of some contractions

  • M. T. Karaev


For the numerical radius of an arbitrary nilpotent operator T on a Hilbert space H, Haagerup and de la Harpe proved the inequality \(w(T) \leqslant \left\| T \right\|cos\frac{\pi }{{n + 1}}\), where n ≥ 2 is the nilpotency order of the operator T. In the present paper, we prove a Haagerup-de la Harpe-type inequality for the numerical radius of contractions from more general classes.


Hilbert Space Hardy Space Toeplitz Operator Shift Operator Numerical Range 
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Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • M. T. Karaev
    • 1
  1. 1.Institute of Mathematics and MechanicsAzerbaijan National Academy of SciencesBakuAzerbaijan

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