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)≤‖T‖cosπ=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.
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机译：对于希尔伯特空间H上任意幂零算子T的数值半径，Haagerup和de la Harpe证明了不等式w（T）≤‖T‖cosπ/ n = 1，其中n≥2是算子T的幂等阶在本文中，我们从更一般的类别证明了收缩的数值半径的Haagerup-de la Harpe型不等式。
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