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  • P-ISSN3059-0604
  • E-ISSN3059-1309
  • KCI

ON p-HYPONORMAL OPERATORS ON A HILBERT SPACE

한국수학교육학회지시리즈B:순수및응용수학 / Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics, (P)3059-0604; (E)3059-1309
1998, v.5 no.2, pp.109-114
Cha, Hyung-Koo (Department of Mathematics, Hanyang University)

Abstract

Let H be a separable complex H be a space and let (equation omitted)(H) be the *-algebra of all bounded linear operators on H. An operator T in (equation omitted)(H) is said to be p-hyponormal if ($T^{\ast}T)^p - (TT^{\ast})^{p}\geq$ 0 for 0 < p < 1. If p = 1, T is hyponormal and if p = $\frac{1}{2}$, T is semi-hyponormal. In this paper, by using a technique introduced by S. K. Berberian, we show that the approximate point spectrum $\sigma_{\alpha p}(T) of a pure p-hyponormal operator T is empty, and obtains the compact perturbation of T.

keywords
polar decomposition, p-hyponormal, spectrum, approximate point spectrum, joint point spectrum, joint approximate point spectrum, trace norm, strongly normal

한국수학교육학회지시리즈B:순수및응용수학