5 documents found

Preprint
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2021-06-09

Perturbations of periodic Sturm-Liouville operators

We study perturbations of self-adjoint periodic Sturm-Liouville operators and conclude under L1-assumptions on the differences of the coeffcients that the essential spectrum and absolutely continuous spectrum remain the same. If a finite first moment condition holds for the differences of the coeffcients,...
Preprint
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2021-04-20

Generalized boundary triples, II. : Some applications of generalized boundary ...

The paper is a continuation of Part I and contains several further results on generalized boundary triples, the corresponding Weyl functions, and applications of this technique to ordinary and partial differential operators. We establish a connection between Post's theory of boundary pairs of closed...
Preprint
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2021-04-20

PT-Symmetric Hamiltonians as couplings of dual pairs

In the seminal paper (Bender & Boettcher, 1998) a new view of quantum mechanics was proposed. This new view differs from the old one in that the restriction on the Hamiltonian to be Hermitian is relaxed: now the Hamiltonian is PT -symmetric. Here P is parity and T is time reversal. Since 1998, PT -symmetric...
Preprint
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2021-01-11

Linear relations and their singular chains

Singular chain spaces for linear relations in linear spaces play a fundamental role in the decomposition of linear relations in finite-dimensional spaces. In this paper singular chains and singular chain spaces are discussed in detail for not necessarily finite-dimensional linear spaces. This leads to...
Preprint
CC BY-NC-ND 3.0
2019

Der Gebietsname Genewara an der Elbe beim Grenzhandelsplatz Magdeburg zu...

Der Name Genewara bezeichnet in den Chroniken zweier südfranzösischer Klöster in einem Bericht (zum Jahr 805) ein Gebiet, welches sich bei Magdeburg befindet und zeitgleich mit einem Feldzug gegen die Böhmen verwüstet wurde. Der Gebietsname Genewara ist bislang nicht befriedigend gedeutet. Bereits ein...

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