Publications Prof. Trunk

Publications of the employees

Publications of the Group

Results: 171
Created on: Thu, 25 Apr 2024 23:11:40 +0200 in 0.0771 sec


Behrndt, Jussi; Leben, Leslie; Martínez Pería, Francisco; Möws, Roland; Trunk, Carsten
Sharp eigenvalue estimates for rank one perturbations of nonnegative operators in Krein spaces. - In: Journal of mathematical analysis and applications, ISSN 1096-0813, Bd. 439 (2016), 2, S. 864-895

http://dx.doi.org/10.1016/j.jmaa.2016.03.012
Gernandt, Hannes; Trunk, Carsten
Eigenvalue placement for regular matrix pencils with rank one perturbations. - Ilmenau : Technische Universität, Institut für Mathematik, 2016. - 1 Online-Ressource (15 Seiten). - (Preprint ; M16,01)

A regular matrix pencil sE-A and its rank one perturbations are considered. We determine the sets in \C\cup\{\infty\} which are the eigenvalues of the perturbed pencil. We show that the largest Jordan chains at each eigenvalue of sE-A may disappear and the sum of the length of all destroyed Jordan chains is the number of eigenvalues (counted with multiplicities) which can be placed arbitrarily in \C\cup\{\infty\}. We prove sharp upper and lower bounds of the change of the algebraic and geometric multiplicity of an eigenvalue under rank one perturbations. Finally we apply our results to a pole placement problem for a single-input differential algebraic equation with feedback.



http://www.db-thueringen.de/servlets/DocumentServlet?id=27311
Berger, Thomas; Trunk, Carsten; Winkler, Henrik
Linear relations and the Kronecker canonical form. - In: Linear algebra and its applications, ISSN 0024-3795, Bd. 488 (2016), S. 13-44

http://dx.doi.org/10.1016/j.laa.2015.09.033
Philipp, Friedrich; Trunk, Carsten
Spectral points of type π+ and type π- of closed operators in indefinite inner product spaces. - In: Operators and matrices, Bd. 9 (2015), 3, S. 481-506
Im Titel ist "+" und "-" tiefgestellt

http://dx.doi.org/10.7153/oam-09-30
Trunk, Carsten;
Locally definitizable operators: the local structure of the spectrum. - In: Operator theory, (2015), S. 241-259

Berger, Thomas; Trunk, Carsten; Trunk, Carsten *1968-*; Winkler, Henrik;
Linear relations and the Kronecker canonical form. - Ilmenau : Techn. Univ., Inst. für Mathematik, 2015. - Online-Ressource (PDF-Datei: 27 S., 402 KB). - (Preprint ; M15,05)

We show that the Kronecker canonical form (which is a canonical decomposition for pairs of matrices) is the representation of a linear relation in a finite dimensional space. This provides a new geometric view upon the Kronecker canonical form. Each of the four entries of the Kronecker canonical form has a natural meaning for the linear relation which it represents. These four entries represent the Jordan chains at finite eigenvalues, the Jordan chains at infinity, the so-called singular chains and the multi-shift part. Or, to state it more concise: For linear relations the Kronecker canonical form is the analogue of the Jordan canonical form for matrices.



http://www.db-thueringen.de/servlets/DocumentServlet?id=26272
Behrndt, Jussi; Leben, Leslie; Martínez Pería, Francisco; Trunk, Carsten
The effect of finite rank perturbations on Jordan chains of linear operators. - In: Linear algebra and its applications, ISSN 0024-3795, Bd. 479 (2015), S. 118-130

http://dx.doi.org/10.1016/j.laa.2015.04.007
Azizov, Tomas Ya.; Trunk, Carsten
On a class of Sturm-Liouville operators which are connected to PT symmetric problems. - In: Proceedings in applied mathematics and mechanics, ISSN 1617-7061, Bd. 14 (2014), 1, S. 991-992

http://dx.doi.org/10.1002/pamm.201410476
Huang, Junjie; Sun, Junfeng; Chen, Alatancang; Trunk, Carsten
The invertibility of 2 x 2 operator matrices. - Ilmenau : Techn. Univ., Inst. für Mathematik, 2014. - Online-Ressource (PDF-Datei: 19 S., 305 KB). - (Preprint ; M14,10)

In this paper the properties of right invertible row operators, i.e., of 1x2 surjective operator matrices are studied. This investigation is based on a specific space decomposition. Using this decomposition, we characterize the invertibility of a 2x2 operator matrix. As an application, the invertibility of Hamiltonian operator matrices is investigated.



http://www.db-thueringen.de/servlets/DocumentServlet?id=25047
Jacob, Birgit; Langer, Matthias; Langer, Matthias *1972-*; Trunk, Carsten;
Variational principles for self-adjoint operator functions arising from second-order systems. - Ilmenau : Techn. Univ., Inst. für Mathematik, 2014. - Online-Ressource (PDF-Datei: 30 S., 455 KB). - (Preprint ; M14,09)
http://www.db-thueringen.de/servlets/DocumentServlet?id=25046