数学物理学报 ›› 2011, Vol. 31 ›› Issue (5): 1385-1392.

• 论文 • 上一篇    下一篇

关于Hilbert空间上算子乘积有限和的奇异值不等式

方莉1|张海燕2   

  1. 1.西北大学 数学系 |西安 710127|2.商丘师范大学 数学系 |河南商丘 476000
  • 收稿日期:2009-12-09 修回日期:2010-12-29 出版日期:2011-10-25 发布日期:2011-10-25
  • 基金资助:

    国家自然科学数学天元基金(11026134)和陕西省教育厅科学研究计划(09JK741)资助

Singular Value Inequalities for Finite Sum of Products of Operators on Hilbert Space

 FANG Li1, ZHANG Hai-Yan2   

  1. 1.Department of Mathematics, Northwest University, Xi'an 710127;
    2.Department of Mathematics, Shangqiu Normal University, Henan Shangqiu 476000
  • Received:2009-12-09 Revised:2010-12-29 Online:2011-10-25 Published:2011-10-25
  • Supported by:

    国家自然科学数学天元基金(11026134)和陕西省教育厅科学研究计划(09JK741)资助

摘要:

Ak, Bk, Xkl (k, l=1, 2, …, n)是可分Hilbert空间H上的有界线性算子.该文证明了: 如果Xkl (k, l=1, 2, …, n)是紧算子, 则对于j=1, 2, …有

sj(k,l=1nAkXklBl)k=1n|Ak|2l=1n|Bk|2sj((Xkl)n×n)  (j=1,2,),

其中||•||是算子范数且( Xkl)n×n是$\oplusk=1nH上的算子定义如下
$$( X_{kl})_{n\times n}=\left(\begin{array}{ccc}X_{11}&~~\cdots ~~&X_{1n}\\\vdots&\ddots&\vdots\\X_{n1}&\cdots &X_{nn}\end{array}\right).

关键词: 奇异值, 算子乘积, 紧算子, 不等式

Abstract:

Let Ak,Bk,Xkl (k=1,2,,n, and l=1,2,,n) be bounded linear operators on a complex separable Hilbert space H. In the present paper, it is shown that if Xkl (k,l=1,2,,n) are compact, then

sj(k,l=1nAkXklBl)k=1n|Ak|2l=1n|Bk|2sj((Xkl)n×n)

for j=1,2,, where is the usual operator norm and (Xkl)n×n is the operator defined on

k=1nH by $( X_{kl})_{n\times n} =\left(\begin{array}{ccc}X_{11}&~~\cdots~~ &X_{1n}\\\vdots&\ddots&\vdots\\X_{n1}&\cdots &X_{nn}\end{array}\right).

Key words: Singular value, Products of operators, Compact operator, Inequality

中图分类号: 

  • 47A30