Search Results - "DIJKSMA, A"

On Nudel’man’s Problem and Indefinite Interpolation in the Generalized Schur and Nevanlinna Classes by Alpay, D., Dijksma, A., Rovnyak, J.

“…This work is a revised and corrected version of the authors’ joint paper with T. Constantinescu (Trans Am Math Soc 355:813–836, 2003). Some of the theorems…”
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On the reproducing kernel of a Pontryagin space of vector valued polynomials by Ćurgus, B., Dijksma, A.

“…We give necessary and sufficient conditions under which the reproducing kernel of a Pontryagin space of d×1 vector polynomials is determined by a generalized…”
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Spectral problems for operator matrices by Bátkai, A., Binding, P., Dijksma, A., Hryniv, R., Langer, H.

“…We study spectral properties of 2 × 2 block operator matrices whose entries are unbounded operators between Banach spaces and with domains consisting of…”
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Jł-unitary factorization and the Schur algorithm for Nevanlinna functions in an indefinite setting by ALPAY, D, DIJKSMA, A, LANGER, H

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High Order Singular Rank One Perturbations of a Positive Operator by Dijksma, A., Kurasov, P., Shondin, Yu

“…In this paper self-adjoint realizations in Hilbert and Pontryagin spaces of the formal expression L-alpha = L + <(.),psi >psi are discussed and compared. Here…”
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Factorization of J-unitary matrix polynomials on the line and a Schur algorithm for generalized Nevanlinna functions by Alpay, D, Dijksma, A, Langer, H

“…We prove that a 2×2 matrix polynomial which is J-unitary on the real line can be written as a product of normalized elementary J-unitary factors and a…”
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Notes on interpolation in the generalized Schur class. II. Nudel'man's problem by ALPAY, D, CONSTANTINESCU, T, DIJKSMA, A, ROVNYAK, J

“…An indefinite generalization of Nudel'man's problem is used in a systematic approach to interpolation theorems for generalized Schur and Nevanlinna functions…”
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Some Extensions of Loewner's Theory of Monotone Operator Functions by Alpay, D., Bolotnikov, V., Dijksma, A., Rovnyak, J.

“…Several extensions of Loewner's theory of monotone operator functions are given. These include a theorem on boundary interpolation for matrix-valued functions…”
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On the Loewner problem in the class \mathbf{N}_{\kappa} by Alpay, D., Dijksma, A., Langer, H.

“…Loewner's theorem on boundary interpolation of \mathbf{N}_{\kappa} functions is proved under rather general conditions. In particular, the hypothesis of Alpay…”
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On the Loewner problem in the class Nκ by ALPAY, D, DIJKSMA, A, LANGER, H

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Nonstationary Analogs of the Herglotz Representation Theorem: The Discrete Case by Alpay, D., Dijksma, A., Peretz, Y.

“…For upper triangular operators with nonnegative real part, we derive generalized Herglotz representation theorems in which the main operator is coisometric,…”
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The Schur Algorithm for Generalized Schur Functions II: Jordan Chains and Transformations of Characteristic Functions by Alpay, D., Azizov, T. Ya, Dijksma, A., Langer, H.

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Nonstationary analogues of the Herglotz representation theorem for unbounded operators by Alpay, D., Bolotnikov, V., Dijksma, A., Freydin, B.

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Closedness and Adjoints of Products of Operators, and Compressions by Azizov, T. Ya, Dijksma, A.

“…We reprove and slightly improve theorems of Nudelman and Stenger about compressions of maximal dissipative and self-adjoint operators to subspaces of finite…”
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On Basis Properties of Selfadjoint Operator Functions by Azizov, T.Ya, Dijksma, A., Sukhocheva, L.I.

“…For a selfadjoint operator function we study the existence of a Riesz basis consisting of eigenvectors if not for the whole space then at least for the closed…”
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Compressions of maximal dissipative and self-adjoint linear relations and of dilations by Azizov, T.Ya, Dijksma, A., Wanjala, G.

“…In this paper we generalize results from Stenger (1968) [30], Nudelman (2011) [28] and Azizov and Dijksma (2012) [7] to maximal dissipative and self-adjoint…”
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Hilbert spaces contractively included in the Hardy Space of the Bidisk by ALPAY, D, BOLOTNIKOV, V, DIJKSMA, A, SADOSKY, C

“…We study the reproducing kernel Hilbert spaces {\mathfrak H}({\mathbb D}2,S) with kernels of the form \frac{I-S(z1,z2)S(w1,w2)*}{(1-z1w1*) (1-z2w2*)} where…”
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On Some Operator Colligations and Associated Reproducing Kernel Pontryagin Spaces by Alpay, D., Bolotnikov, V., Dijksma, A., de Snoo, H.

“…Letsbe a Schur function, that is a function analytic and contractive in the unit disk D. Then the function 1−s(z)s(ω)*/1−zω* is positive in D. L. de Branges…”
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On the Nevanlinna-Pick interpolation problem for generalized stieltjes functions by Alpay, D., Bolotnikov, V., Dijksma, A.

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On the Closedness of Operator Pencils by Azizov, T. Ya, Dijksma, A., Förster, K.-H., Glaskova, M. Yu

“…Consider an operator pencil A0 + λ1A1 +... + λnAn in which, for example (other cases are also considered), A0 is a maximal accretive operator, A1,..., An are…”
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