New perturbation bounds in unitarily invariant norms for subunitary polar factors

2018 ◽  
Vol 34 ◽  
pp. 231-239
Author(s):  
Lei Zhu ◽  
Wei-wei Xu ◽  
Hao Liu ◽  
Li-juan Ma

Let $A\in\mathbb{C}^{m \times n}$ have generalized polar decomposition $A = QH$ with $Q$ subunitary and $H$ positive semidefinite. Absolute and relative perturbation bounds are derived for the subunitary polar factor $Q$ in unitarily invariant norms and in $Q$-norms, that extend and improve existing bounds.

2012 ◽  
Vol 2012 ◽  
pp. 1-15
Author(s):  
Pingping Zhang ◽  
Hu Yang ◽  
Hanyu Li

Some new perturbation bounds for both weighted unitary polar factors and generalized nonnegative polar factors of the weighted polar decompositions are presented without the restriction thatAand its perturbed matrixA˜have the same rank. These bounds improve the corresponding recent results.


2004 ◽  
Vol 44 (2) ◽  
pp. 237-244 ◽  
Author(s):  
Xiao-shan Chen ◽  
Wen Li ◽  
Weiwei Sun

2014 ◽  
Vol 233 ◽  
pp. 430-438 ◽  
Author(s):  
Xiaoli Hong ◽  
Lingsheng Meng ◽  
Bing Zheng

2013 ◽  
Vol 61 (4) ◽  
pp. 517-526
Author(s):  
Pingping Zhang ◽  
Hu Yang ◽  
Hanyu Li

1984 ◽  
Vol 36 (6) ◽  
pp. 973-985
Author(s):  
Bryan E. Cain

The results in this paper respond to two rather natural questions about a polar decomposition A = UP, where U is a unitary matrix and P is positive semidefinite. Let λ1, …, λn be the eigenvalues of A. The questions are:(A) When will |λ1|, …, |λn| be the eigenvalues of P?(B) When will λ1/|λ1|, …, λn/|λn| be the eigenvalues of U?The complete answer to (A) is “if and only if U and P commute.” In an important special case the answer to (B) is “if and only if U2 and P commute.“Since these matters are best couched in terms of two different inertias, we begin with a unifying definition of inertia which views all inertias from a single perspective.For each square complex matrix A and each complex number z let m(A, z) denote the multiplicity of z as a root of the characteristic polynomial


Author(s):  
N.D. Christov ◽  
S. Lesecq ◽  
M.M. Konstantinov ◽  
P.Hr. Petkov ◽  
A. Barraud

Sign in / Sign up

Export Citation Format

Share Document