

It is well known that the spectrum of a given matrix A belongs to the Geršgorin set Γ(A), as well as to the Geršgorin set applied to the transpose of A, Γ(AT). So, the spectrum belongs to their intersection. But, if we first intersect i-th Geršgorin disk Γi(A) with the corresponding disk Γi(AT) and then we make union of such intersections, which are, in fact, the smaller disks of each pair, what we get is not an eigenvalue localization area. The question is what should be added in order to catch all the eigenvalues, while, of course, staying within the set Γ(A) ∩ Γ(AT). The answer lies in the appropriate characterization of some subclasses of nonsingular H-matrices. In this paper we give two such characterizations, and then we use them to prove localization areas that answer this question. © 2009 Springer Science+Business Media, LLC.
| Funding sponsor | Funding number | Acronym |
|---|---|---|
| MTM2007-64477 | ||
| Ministry of Science and Environmental Protection | 144025 | |
| Universitat Politècnica de València | UPV | |
| Provincial Secretariat for Science and Technological Development | 0708 | PSSTD |
Acknowledgements This work is supported by the agreement of research cooperation between University of Novi Sad (Serbia) and Universitat Politècnica de València (Spain), by Spanish DGI grant MTM2007-64477, by the Provincial Secretariat of Science and Technological Development of Vojvodina, Serbia, grant 0708 and by the Ministry of Science and Environmental Protection of Serbia, grant 144025.
Pedroche, F.; Institut de Matemàtica Multidisciplinária, Universitat Politècnica de València, Camí de Vera s/n., Spain;
© Copyright 2011 Elsevier B.V., All rights reserved.