Search Results - Linear operators on spaces with an indefinite metric

The numerical range of banded 2-Toeplitz operators in spaces with an indefinite metric by Bebiano, N., da Providência, J., Nata, A.

“…The numerical range of banded -Toeplitz operators acting on a Hilbert space endowed with an indefinite metric is investigated…”
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Spectral inclusion properties of the numerical range in a space with an indefinite metric by Wu, Deyu, Chen, Alatancang

“…In this paper the numerical range of operators (possibly unbounded) in an indefinite inner product space is studied…”
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J-states and quantum channels between indefinite metric spaces by Felipe-Sosa, Raúl, Felipe, Raúl

“…In the present work, we introduce and study the concepts of state and quantum channel on spaces equipped with an indefinite metric…”
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Linear maps preserving G-quasi-isometry operators by Chahbi, Abdellatif, EL-Fassi, Iz-iddine, Kabbaj, Samir

“…Let H be a complex Hilbert space and B ( H ) the algebra of all bounded linear operators on H…”
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On linear maps that preserve G-partial-isometries in Hilbert space by Chahbi, Abdellatif, Kabbaj, Samir

“…Let Ti be a complex Hilbert space and B(TT) the algebra of all bounded linear operators on H…”
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Linear maps preserving G-unitary operators in Hilbert space by Abdellatif Chahbi, Samir Kabbaj

“…Let H be a complex Hilbert space and B(H) the algebra of all bounded linear operators on H…”
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Extreme fixed points of operator LFT, applications to the Königs problem by Khatskevich, V.A., Senderov, V.A.

“… We show that a wide class of fractional-linear mappings with a fixed point on the boundary of the unit operator ball D have the KE-property…”
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On Krein's formula in indefinite metric spaces by Belyi, Sergey, Tsekanovskii, Eduard

“…–Titchmarsh functions in the spaces with indefinite metrics. We show that coefficients in Krein's formula can be expressed in terms of analogues of the von Neumann parametrization formulas in the indefinite case…”
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Truncated Wigner approximation as a non-positive Kraus map by Klimov, A B, Sainz, I, Romero, J L

“…We show that the Truncated Wigner Approximation developed in the flat phase-space is mapped into a Lindblad-type evolution with an indefinite metric in the space of linear operators…”
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Positive Decompositions of Selfadjoint Operators by Fongi, Guillermina, Maestripieri, Alejandra

“…Given a linear bounded selfadjoint operator a on a complex separable Hilbert space , we study the decompositions of a as a difference of two positive operators whose ranges satisfy an angle condition…”
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Koenigs problem and extreme fixed points by Senderov, V. A., Khatskevich, V. A.

“…This note continues some previous studies by the authors. We consider a linear-fractional mapping generated by a triangular operator, where is the unit operator…”
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On realization of the Kreĭn-Langer class Nκ of matrix-valued functions in Pontryagin spaces by Arlinskiĭ, Yury, Belyi, Sergey, Derkach, Vladimir, Tsekanovskii, Eduard

“… Livsic type (Brodskii–Livsic rigged operator colligation) with the main operator acting on a rigged Pontryagin space Πκ…”
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Numerical ranges of Toeplitz operators with matrix symbols by Bebiano, Natalia, Spitkovsky, Ilya M.

“…For Toeplitz operators acting on the vector Hardy space H2 with definite or indefinite metric, the closure of the respective numerical range is completely described…”
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On the bicommutant for one type of J-symmetric nilpotent algebras in Krein spaces by Strauss, Vladimir

“…In the present paper we shall consider an operator algebra in a Krein space. One of the interesting questions that arises in this area is a relationship between the algebra and its bicommutant…”
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Stability of a Generalized Sobolev System by Fraguela, Andrés, González, Alma L., Felipe, Raúl

“…The linear stability problem of the rotational motion of a rigid body around a fixed point containing an inner cavity filled up with an ideal fluid is considered…”
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Some comments on the properties of unitary transformations on linear spaces having an indefinite metric and the connection with the theory of spin by L wdin, Per-Olov

“…After a brief review of the history of the discovery of the spin, some fundamental properties of linear spaces having an indefinite metric are being discussed…”
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Convexity and weak closedness of the image of operator balls under linear-fractional transformations by Azizov, T. Ya, Kiriakidi, V. K.

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Beurling-Lax type theorems and Cuntz relations by Alpay, Daniel, Colombo, Fabrizio, Sabadini, Irene, Schneider, Baruch

“… Applications to the theory of de Branges-Rovnyak spaces, also in the indefinite metric setting, are given…”
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Solvability of Boundary Value Problems for Operator-Differential Equations of Mixed Type: The Degenerate Case by Pyatkov, S. G., Abasheeva, N. L.

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A Comment on Background Independence in Quantum Theory by Brandas, Erkki J

“…‐energy portrait in nexus with its space‐time conjugates. The description is based on operator matrix algebra, where the related analogue of the secular equation yields a Klein…”
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