Eigenvalue estimates for operators with finitely many negative squares. - In: Opuscula mathematica, ISSN 2300-6919, Bd. 36 (2016), 6, S. 717-734
https://doi.org/10.7494/OpMath.2016.36.6.717
On stability of closedness and self-adjointness for 2 x 2 operator matrices. - In: Mathematical notes, ISSN 1573-8876, Bd. 100 (2016), 5, S. 870-875
http://dx.doi.org/10.1134/S0001434616110274
Variational principles for self-adjoint operator functions arising from second-order systems. - In: Operators and matrices, Bd. 10 (2016), 3, S. 501-531
http://dx.doi.org/10.7153/oam-10-29
Bounds on the non-real spectrum of a singular indefinite Sturm-Liouville operator on R. - In: Proceedings in applied mathematics and mechanics, ISSN 1617-7061, Bd. 16 (2016), 1, S. 881-882
http://dx.doi.org/10.1002/pamm.201610429
On the parametric eigenvalue behavior of matrix pencils under rank one perturbations. - In: Proceedings in applied mathematics and mechanics, ISSN 1617-7061, Bd. 16 (2016), 1, S. 873-874
http://dx.doi.org/10.1002/pamm.201610425
Limit-point/limit-circle classification of second-order differential operators arising in PT quantum mechanics. - In: Proceedings in applied mathematics and mechanics, ISSN 1617-7061, Bd. 16 (2016), 1, S. 871-872
http://dx.doi.org/10.1002/pamm.201610424
Ob ustojčivosti zamknutosti i samosoprjažennosti dlja 2 x 2 operator-matric. - Ilmenau : Technische Universität, Institut für Mathematik, 2016. - 1 Online-Ressource (6 Seiten). - (Preprint ; M16,07)
Consider an operator which is defined in Banach or Hilbert space by a 2x2 matrix with entries A, B, C, D which where linear operators and which are assumed to be unbounded. In the case when the operators C and B are relatively bounded with respect to the operators A and D, respectively, new conditions of the closeness or closability are obtained for the operator L. For the operator L acting in a Hilbert space the analogs of Rellich-Kato theorems on the stability of self-adjointness are obtained.
https://www.db-thueringen.de/receive/dbt_mods_00030580
Non-negative operators in Krein spaces and rank one perturbations. - Ilmenau : Universitätsverlag Ilmenau, 2016. - Online-Ressource (116 Seiten, 6.65 MB)
Technische Universität Ilmenau, Dissertation 2016
In der vorliegenden Arbeit werden eindimensionale Störungen von nichtnegativen Operatoren in Kreinräumen betrachtet. Dabei wird untersucht wie sich die Anzahl der Eigenwerte und deren Vielfachheit in einer Lücke des essentiellen Spektrums unter einer Störung ändern können. Zudem wird beschrieben wie sich an einem Eigenwert die Anzahl und die Länge der linear unabhängigen Jordanketten ändern können.
https://www.db-thueringen.de/receive/dbt_mods_00029981
Limit-point/limit-circle classification of second-order differential operators arising in PT quantum mechanics. - Ilmenau : Technische Universität, Institut für Mathematik, 2016. - 1 Online-Ressource (6 Seiten). - (Preprint ; M16,03)
https://www.db-thueringen.de/receive/dbt_mods_00029270
Bounds on the non-real spectrum of a singular indefinite Sturm-Liouville operator on R. - Ilmenau : Technische Universität, Institut für Mathematik, 2016. - 1 Online-Ressource (4 Seiten). - (Preprint ; M16,05)
A simple explicit bound on the absolute values of the non-real eigenvalues of a singular indefinite Sturm-Liouville operator on the real line with the weight function sgn(&hahog;) and an integrable, continuous potential q is obtained.
https://www.db-thueringen.de/receive/dbt_mods_00029271