a Indian Statistical Institute, New Delhi, India
b Department of Mathematics, University of Jordan, Amman, Jordan
c Mathematical Science Section, Oak Ridge National Laboratory, Oak Ridge, TN
Abstract:
Inequalities that compare unitarily invariant norms of A - B and those of AΓ - ΓB and Γ-1A - B Γ-1 are obtained, where both A and B are either Hermitian or unitary or normal operators and Γ is a positive definite operator in a complex separable Hilbert space. These inequalities are then applied to derive bounds for spectral variation of diagonalisable matrices. Our new bounds improve substantially previously published bounds.