Square roots of semihyponormal operators have scalar extensions.
type: Item
instance of: scholarly article
title: Square roots of semihyponormal operators have scalar extensions.
zbMATH Open document ID: 1058.47019
DOI: 10.1016/S0007-4497(03)00040-X
author: Eungil Ko
published in: Bulletin des Sciences Mathématiques
publication date: 2003-09-15T00:00:00Z
review text: A Hilbert space operator \(T\in B(H)\) is semi-hyponormal if \(|T^*|\leq |T|\). The author continues his study of the classes of Hilbert space operators which are subscalar. Here, the author proves that if \(T\) is the square root of a semi-hyponormal operator (i.e., \(T\in B(H)\) is such that \(T^2\) is semi-hyponormal), then \(T\) is subscalar of order \(4\). Applications, mostly routine, are considered.
Mathematics Subject Classification ID: 47B20
Mathematics Subject Classification ID: 47B38
Mathematics Subject Classification ID: 47B40
zbMATH DE Number: 1981490
zbMATH Keywords: Hilbert space
zbMATH Keywords: semi-hyponormal operator
zbMATH Keywords: subscalar operator
zbMATH Keywords: Bishop's property \((\beta)\)
reviewed by: B. P. Duggal
MaRDI profile type: Publication
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description: scientific article; zbMATH DE number 1981490