WANG Yue-qing, DU Hong-ke, ZUO Ning
(College of Mathematics and Information Science, Shaanxi Normal University, Xi′an 710062, Shaanxi, China)
Abstract:
Based on the definition of the unitarily invariant norm of operators, some properties of the 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.
KeyWords:
operator inequality; unitarily invariant norm; positive operator
