Title
Some Regularity Results for the Pseudospectral Abscissa and Pseudospectral Radius of a Matrix.
Abstract
The epsilon-pseudospectral abscissa alpha(epsilon) and radius rho(epsilon) of an n x n matrix are, respectively, the maximal real part and the maximal modulus of points in its epsilon-pseudospectrum, defined using the spectral norm. It was proved in [A.S. Lewis and C.H.J. Pang, SIAM J. Optim., 19 (2008), pp. 1048-1072] that for fixed epsilon > 0, alpha(epsilon) and rho(epsilon) are Lipschitz continuous at a matrix A except when alpha(epsilon) and rho(epsilon) are attained at a critical point of the norm of the resolvent (in the nonsmooth sense), and it was conjectured that the points where alpha(epsilon) and rho(epsilon) are attained are not resolvent-critical. We prove this conjecture, which leads to the new result that alpha(epsilon) and rho(epsilon) are Lipschitz continuous, and also establishes the Aubin property with respect to both epsilon and A of the epsilon-pseudospectrum for the points z is an element of C where alpha(epsilon) and rho(epsilon) are attained. Finally, we give a proof showing that the pseudospectrum can never be "pointed outwards."
Year
DOI
Venue
2012
10.1137/110822840
SIAM JOURNAL ON OPTIMIZATION
Keywords
Field
DocType
pseudospectrum,pseudospectral abscissa,pseudospectral radius,eigenvalue perturbation,Lipschitz multifunction,Aubin property
Discrete mathematics,Mathematical optimization,Pseudospectrum,Abscissa,Matrix (mathematics),Resolvent,Matrix norm,Critical point (thermodynamics),Lipschitz continuity,Conjecture,Mathematics
Journal
Volume
Issue
ISSN
22
2
1052-6234
Citations 
PageRank 
References 
2
0.42
2
Authors
2
Name
Order
Citations
PageRank
Mert Gürbüzbalaban15512.36
Michael L. Overton2634590.15