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Mark Malamud

Bio: Mark Malamud is an academic researcher from Peoples' Friendship University of Russia. The author has contributed to research in topics: Operator (computer programming) & Matrix (mathematics). The author has an hindex of 29, co-authored 166 publications receiving 3736 citations. Previous affiliations of Mark Malamud include National Academy of Sciences of Ukraine & Donetsk National University.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a Hermitian operator A with gaps (αj, βj) (1 ⩽ j⩽ m ⩾ ∞) is studied and the self-adjoint extensions which put exactly kj < ∞ eigenvalues into each gap are described in terms of boundary conditions.

598 citations

Journal ArticleDOI
TL;DR: In this paper, the concepts of boundary relations and the corresponding Weyl families are introduced, and fruitful connections between certain classes of holomorphic families of linear relations on the complex Hilbert space H and the class of unitary relations Gamma : (H 2, J(H)) -> (H-2, J (H)), where Gamma need not be surjective and is even allowed to be multivalued.
Abstract: The concepts of boundary relations and the corresponding Weyl families are introduced. Let S be a closed symmetric linear operator or, more generally, a closed symmetric relation in a Hilbert space h, let H be an auxiliary Hilbert space, let [GRAPHICS] and let JH be defined analogously. A unitary relation G from the Krein space (h(2), J(h)) to the Kre. in space (H-2, J(H)) is called a boundary relation for the adjoint S* if ker Gamma = S. The corresponding Weyl family M(lambda) is de. ned as the family of images of the defect subspaces (n) over cap (lambda), lambda is an element of C \ R under Gamma. Here Gamma need not be surjective and is even allowed to be multi-valued. While this leads to fruitful connections between certain classes of holomorphic families of linear relations on the complex Hilbert space H and the class of unitary relations Gamma : ( H-2, J(H)) -> (H-2, J(H)), it also generalizes the notion of so-called boundary value space and essentially extends the applicability of abstract boundary mappings in the connection of boundary value problems. Moreover, these new notions yield, for instance, the following realization theorem: every H-valued maximal dissipative (for lambda is an element of C+) holomorphic family of linear relations is the Weyl family of a boundary relation, which is unique up to unitary equivalence if certain minimality conditions are satisfied. Further connections between analytic and spectral theoretical properties of Weyl families and geometric properties of boundary relations are investigated, and some applications are given.

172 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the formal deficiency indices N ± of a symmetric first-order system Jf′+Bf=λ H f on an interval I, where I = R or I= R ±.

140 citations

Journal ArticleDOI
TL;DR: In this article, the authors considered the case d ∗ = 0 and obtained necessary and sufficient conditions for the operators H X, α to be self-adjoint, lower semibounded, and discrete.

128 citations


Cited by
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01 Jan 2016
TL;DR: The methods of modern mathematical physics is universally compatible with any devices to read and is available in the digital library an online access to it is set as public so you can download it instantly.
Abstract: Thank you very much for reading methods of modern mathematical physics. Maybe you have knowledge that, people have look numerous times for their favorite novels like this methods of modern mathematical physics, but end up in harmful downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they are facing with some infectious virus inside their desktop computer. methods of modern mathematical physics is available in our digital library an online access to it is set as public so you can download it instantly. Our books collection saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the methods of modern mathematical physics is universally compatible with any devices to read.

1,536 citations

DissertationDOI
01 Jan 2002

700 citations

J.A. Ball, Harry Dym, Kaashoek, H. Langer, C. Tretter 
01 Jan 2008
TL;DR: In this paper, the authors present a series devoted to the publication of current research in operator theory, with particular emphasis on applications to classical analysis and the theory of integral equations, as well as to numerical analysis, mathematical physics and mathematical methods in electrical engineering.
Abstract: Edited by Joseph A. Ball (Blacksburg, VA, USA) Harry Dym (Rehovot, Israel) Marinus A. Kaashoek (Amsterdam, The Netherlands) Heinz Langer (Vienna, Austria) Christiane Tretter (Bern, Switzerland) Associate Editors: Vadim Adamyan, Wolfgang Arendt, Albrecht Bottcher, B. Malcolm Brown, Raul Curto, Fritz Gesztesy, Pavel Kurasov, Vern Paulsen, Mihai Putinar, Ilya M. Spitkovsky This series is devoted to the publication of current research in operator theory, with particular emphasis on applications to classical analysis and the theory of integral equations, as well as to numerical analysis, mathematical physics and mathematical methods in electrical engineering.

406 citations