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 $n \geq 2$ 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.
How to Cite
Karaev, M. T. “On Estimate for Numerical Radius of Some Contractions”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 58, no. 10, Oct. 2006, pp. 1335–1339, https://umj.imath.kiev.ua/index.php/umj/article/view/3536.
Research articles