正算子和与直和不等式  

Inequalities of sums and direct sums of positive operators

作　　者：王月清[1] 杜鸿科[1] 左宁[1] 

机构地区：[1]陕西师范大学数学与信息科学学院,陕西西安710062

出　　处：《陕西师范大学学报（自然科学版）》2007年第2期18-21,共4页Journal of Shaanxi Normal University：Natural Science Edition

基　　金：国家自然科学基金资助项目(10571113)

摘　　要：基于酉不变范数的定义,讨论了算子和与算子直和的酉不变范数性质,结合2×2算子矩阵的范数不等式以及正算子的一些性质,得到了复可分希尔伯特空间上n个正算子和与直和的不等式,推广了有关文献的结论.Based on the definition of the unitarily invariant norm ot operators, some properties unitarily invariant norm of sums and direct sums of operators are discussed, then by using norm inequalities for 2 × 2 operator matrices and properties of positive operators, some inequalities of sums and direct sums of n positive operators are given, which are generalizations of the related theorems in the literatures.

关 键 词：算子不等式 酉不变范数 正算子 

分 类 号：O177.1[理学—数学]