Document Type
Article
Department/Program
Mathematics
Journal Title
Linear Algebra and Its Applications
Pub Date
2009
Volume
431
Issue
12
First Page
2336
Abstract
Let B(H) be the algebra of bounded linear operator acting on a Hilbert space H (over the complex or real Held). Characterization is given to A(1), ... , A(k) is an element of B(H) such that for any unitary operators U(1), ... , U(k), Sigma(k)(j=1) U(j)*A(j)U(j) is always in a special class S of operators such as normal operators, self-adjoint operators, unitary operators. As corollaries, characterizations are given to A is an element of B(H) such that complex, real or nonnegative linear combinations of operators in its unitary orbit u(A) = {U*AU : Uunitary} always lie in S. (c) 2009 Elsevier Inc. All rights reserved.
Recommended Citation
Poon, Yiu-Tung and Li, Chi-Kwong, The sum of unitary similarity orbits containing only special operators (2009). Linear Algebra and Its Applications, 431(12), 2336-2345.
10.1016/j.laa.2009.03.010
DOI
10.1016/j.laa.2009.03.010
