Operator Theory and Complex Analysis von T. Ando | Workshop on Operator Theory and Complex Analysis Sapporo (Japan) June 1991 | ISBN 9783034886062

Operator Theory and Complex Analysis

Workshop on Operator Theory and Complex Analysis Sapporo (Japan) June 1991

von T. Ando und I. Gohberg
Mitwirkende
Autor / AutorinT. Ando
Autor / AutorinI. Gohberg
Buchcover Operator Theory and Complex Analysis | T. Ando | EAN 9783034886062 | ISBN 3-0348-8606-3 | ISBN 978-3-0348-8606-2

Operator Theory and Complex Analysis

Workshop on Operator Theory and Complex Analysis Sapporo (Japan) June 1991

von T. Ando und I. Gohberg
Mitwirkende
Autor / AutorinT. Ando
Autor / AutorinI. Gohberg

Inhaltsverzeichnis

  • Scattering matrices for microschemes.
  • 1. General expressions for the scattering matrix.
  • 2. Continuity condition.
  • References.
  • Holomorphic operators between Krein spaces and the number of squares of associated kernels.
  • 0. Introduction.
  • 1. Realizations of a class of Schur functions.
  • 2. Positive squares and injectivity.
  • 3. Application of the Potapov-Ginzburg transform.
  • On reproducing kernel spaces, the Schur algorithm, and interpolation in a general class of domains.
  • 1. Introduction.
  • 2. Preliminaries.
  • 3. B(X) spaces.
  • 4. Recursive extractions and the Schur algorithm.
  • 5. H?(S) spaces.
  • 6. Linear fractional transformations.
  • 7. One sided interpolation.
  • 8. References.
  • The central method for positive semi-definite, contractive and strong Parrott type completion problems.
  • 2. Positive semi-definite completions.
  • 3. Contractive completions.
  • 4. Linearly constrained contractive completions.
  • Interpolation by rational matrix functions and stability of feedback systems: The 4-block case.
  • 1. Preliminaries.
  • 2. A homogeneous interpolation problem.
  • 3. Interpolation problem.
  • 4. Parametrization of solutions.
  • 5. Interpolation and internally stable feedback systems.
  • Matricial coupling and equivalence after extension.
  • 2. Coupling versus equivalence.
  • 3. Examples.
  • 4. Special classes of operators.
  • Operator means and the relative operator entropy.
  • 2. Origins of operator means.
  • 3. Operator means and operator monotone functions.
  • 4. Operator concave functions and Jensen’s inequality.
  • 5. Relative operator entropy.
  • An application of Furuta’s inequality to Ando’s theorem.
  • 2. Operator functions.
  • 3. Furuta’s type inequalities.
  • 4. An application to Ando’s theorem.
  • Applications of order preserving operator inequalities.
  • 1. Application to the relative operator entropy.
  • 2. Application to some extended result of Ando’s one.
  • The band extension of the real line as a limit of discrete band extensions, I. The main limit theorem.
  • I. Preliminaries and preparations.
  • II. Band extensions.
  • III. Continuous versus discrete.
  • Interpolating sequences in the maximal ideal space of H? II.
  • 2. Condition (A2).
  • 3. Condition (A3).
  • 4. Condition (A1).
  • Operator matrices with chordal inverse patterns.
  • 2. Entry formulae.
  • 3. Inertia formula.
  • Models and unitary equivalence of cyclic selfadjoint operators in Pontrjagin spaces.
  • 1. The class F of linear functionals.
  • 2. The Pontrjagin space associated with ? ? F.
  • 3. Models for cyclic selfadjoint operators in Pontrjagin spaces.
  • 4. Unitary equivalence of cyclic selfadjoint operators in Pontrjagin spaces.
  • The von Neumann inequality and dilation theorems for contractions.
  • 1. The von Neumann inequality and strong unitary dilation.
  • 2. Canonical representation of completely contractive maps.
  • 3. An effect of generation of nuclear algebras.
  • Interpolation problems, inverse spectral problems and nonlinear equations.
  • Extended interpolation problem in finitely connected domains.
  • I. Matrices and transformation formulas.
  • II. Disc Cases.
  • III. Domains of finite connectivity.
  • Accretive extensions and problems on the Stieltjes operator-valued functions relations.
  • 1. Accretive and sectorial extensions of the positive operators, operators of the class C(?) and theirparametric representation.
  • 2. Stieltjes operator-valued functions and their realization.
  • 3. M. S. Livsic triangular model of the M-accretive extensions (with real spectrum) of the positive operators.
  • 4. Canonical and generalized resolvents of QSC-extensions of Hermitian contractions.
  • Commuting nonselfadjoint operators and algebraic curves.
  • 1. Commuting nonselfadjoint operators and the discriminant curve.
  • 2. Determinantal representations of real plane curves.
  • 3. Commutative operator colligations.
  • 4. Construction of triangular models: Finite-dimensional case.
  • 5. Construction of triangular models: General case.
  • 6. Characteristic functions and the factorization theorem.
  • All (?) about quasinormal operators.
  • 2. Representations.
  • 3. Spectrum and multiplicity.
  • 4. Special classes.
  • 5. Invariant subspaces.
  • 6. Commutant.
  • 7. Similarity.
  • 8. Quasisimilarity.
  • 9. Compact perturbation.
  • 10. Open problems.
  • Workshop Program.
  • List of Participants.