FURTHER INEQUALITIES FOR THE NUMERICAL RADIUS OF HILBERT SPACE OPERATORS

被引：23
|
作者：
Tafazoli, Sara [1 ]
Moradi, Hamid Reza [2 ]
Furuichi, Shigeru [3 ]
Harikrishnan, Panackal [4 ]
机构：
[1] Islamic Azad Univ, Dept Math, Hormoz Branch, Hormoz Isl, Iran
[2] PNU, Dept Math, POB 19395-4697, Tehran, Iran
[3] Nihon Univ, Dept Informat Sci, Coll Humanities & Sci, Setagaya Ku, 3-25-40 Sakurajyousui, Tokyo 1568550, Japan
[4] Manipal Acad Higher Educ, Dept Math, Manipal Inst Technol, Manipal 576104, Karnataka, India
来源：
JOURNAL OF MATHEMATICAL INEQUALITIES | 2019年 / 13卷 / 04期
关键词：
Operator inequality; norm inequality; numerical radius; convex function; f; -; connection; weighted arithmetic-geometric mean inequality;
D O I：
10.7153/jmi-2019-13-68
中图分类号：
O29 [应用数学];
学科分类号：
070104 ;
摘要：
In this article, we present some new inequalities for numerical radius of Hilbert space operators via convex functions. Our results generalize and improve earlier results by E1-Haddad and Kittaneh. Among several results, we show that if A is an element of B (H) and r >= 2 , then w(r) (A) <= parallel to A parallel to(r) - inf(parallel to x parallel to = 1) parallel to vertical bar vertical bar A vertical bar - w (A) vertical bar (r/2) x parallel to(2) where w ( . ) d parallel to.parallel to denote the numerical radius and usual operator norm, respectively.
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页码：955 / 967
页数：13
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