Better bounds on the numerical radii of Hilbert space operators

被引：28
|
作者：
Omidvar, Mohsen Erfanian [1 ]
Moradi, Hamid Reza [2 ]
机构：
[1] Islamic Azad Univ, Mashhad Branch, Dept Math, Mashhad, Razavi Khorasan, Iran
[2] Islamic Azad Univ, Mashhad Branch, Young Researchers & Elite Club, Mashhad, Razavi Khorasan, Iran
来源：
LINEAR ALGEBRA AND ITS APPLICATIONS | 2020年 / 604卷
关键词：
Numerical radius; Operator norm; Operator convex function; Hermite-Hadamard inequality; NORM INEQUALITIES;
D O I：
10.1016/j.laa.2020.06.021
中图分类号：
O29 [应用数学];
学科分类号：
070104 ;
摘要：
Kittaneh proved that if A is a bounded linear operator on a complex Hilbert space, then 1/4 parallel to vertical bar A vertical bar(2) + vertical bar A*vertical bar(2)parallel to <= omega(2) (A), where omega(.) and parallel to.parallel to are the numerical radius and the usual operator norm, and vertical bar A vertical bar = (A*A)(1/2). In this paper, we show that 1/4 parallel to vertical bar A vertical bar(2) + vertical bar A vertical bar(2)parallel to <= 1/2 omega(2) (A)+1/8 parallel to(A+A*) (A-A*)parallel to <=omega(2) (A) Meanwhile, we give an improvement of the norm inequality presented by Bhatia and Kittaneh for the positive operators. (C) 2020 Elsevier Inc. All rights reserved.
引用
收藏
页码：265 / 277
页数：13
相关论文
共 50 条
  • [21] Some Gap Relations Between Operator Norm with Spectral and Numerical Radii of Direct Sum Hilbert Space Operators
    Cevik, E. Otkun
    Ismailov, Z. I.
    LOBACHEVSKII JOURNAL OF MATHEMATICS, 2022, 43 (02) : 366 - 375
  • [22] Some Gap Relations Between Operator Norm with Spectral and Numerical Radii of Direct Sum Hilbert Space Operators
    E. Otkun Çevik
    Z. I. Ismailov
    Lobachevskii Journal of Mathematics, 2022, 43 : 366 - 375
  • [23] New upper bounds for the numerical radius of operators on Hilbert spaces
    Sahoo, Satyajit
    Rout, Nirmal Chandra
    ADVANCES IN OPERATOR THEORY, 2022, 7 (04)
  • [24] New upper bounds for the numerical radius of operators on Hilbert spaces
    Satyajit Sahoo
    Nirmal Chandra Rout
    Advances in Operator Theory, 2022, 7
  • [25] Some Upper Bounds for the Berezin Number of Hilbert Space Operators
    Taghavi, Ali
    Roushan, Tahere Azimi
    Darvish, Vahid
    FILOMAT, 2019, 33 (14) : 4353 - 4360
  • [26] Bounds for the Berezin number of reproducing kernel Hilbert space operators
    Sen, Anirban
    Bhunia, Pintu
    Paul, Kallol
    FILOMAT, 2023, 37 (06) : 1741 - 1749
  • [27] ON PSEUDOSPECTRAL RADII OF OPERATORS ON HILBERT SPACES
    Jia, Boting
    Feng, Youling
    ANNALS OF FUNCTIONAL ANALYSIS, 2018, 9 (04): : 474 - 484
  • [28] REDUCED MINIMAL NUMERICAL RANGES OF OPERATORS ON A HILBERT SPACE
    Du Hongke
    Wang Yueqing
    Lu Jianming
    ACTA MATHEMATICA SCIENTIA, 2009, 29 (01) : 94 - 100
  • [29] Norm and numerical radius inequalities for Hilbert space operators
    Moosavi, Baharak
    Hosseini, Mohsen Shah
    JOURNAL OF ANALYSIS, 2023, 31 (02): : 1393 - 1400
  • [30] REDUCED MINIMAL NUMERICAL RANGES OF OPERATORS ON A HILBERT SPACE
    杜鸿科
    王月清
    陆建明
    ActaMathematicaScientia, 2009, 29 (01) : 94 - 100
12345