The Commutant Lifting Approach to Interpolation Problems

The Commutant Lifting Approach to Interpolation Problems PDF Author: Foias
Publisher: Birkhäuser
ISBN: 3034877129
Category : Science
Languages : en
Pages : 647

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Book Description
Classical H interpolation theory was conceived at the beginning of the century by C. Caratheodory, L. Fejer and I. Schur. The basic method, due to Schur, in solving these problems consists in applying the Mobius transform to peel off the data. In 1967, D. Sarason encompassed these classical interpolation problems in a representation theorem of operators commuting with special contractions. Shortly after that, in 1968, B. Sz. Nagy and C. Foias obtained a purely geometrical extension of Sarason's results. Actually, their result states that operators intertwining restrictions of co-isometries can be extended, by preserving their norm, to operators intertwining these co-isometries; starring with R. G. Douglas, P. S. Muhly and C. Pearcy, this is referred to as the commutant lifting theorem. In 1957, Z. Nehari considered an L interpolation problern which in turn encompassed the same classical interpolation problems, as well as the computation of the distance of a function f in L to H . At about the sametime as Sarason's work, V. M."

The Commutant Lifting Approach to Interpolation Problems

The Commutant Lifting Approach to Interpolation Problems PDF Author: Foias
Publisher: Birkhäuser
ISBN: 3034877129
Category : Science
Languages : en
Pages : 647

Get Book Here

Book Description
Classical H interpolation theory was conceived at the beginning of the century by C. Caratheodory, L. Fejer and I. Schur. The basic method, due to Schur, in solving these problems consists in applying the Mobius transform to peel off the data. In 1967, D. Sarason encompassed these classical interpolation problems in a representation theorem of operators commuting with special contractions. Shortly after that, in 1968, B. Sz. Nagy and C. Foias obtained a purely geometrical extension of Sarason's results. Actually, their result states that operators intertwining restrictions of co-isometries can be extended, by preserving their norm, to operators intertwining these co-isometries; starring with R. G. Douglas, P. S. Muhly and C. Pearcy, this is referred to as the commutant lifting theorem. In 1957, Z. Nehari considered an L interpolation problern which in turn encompassed the same classical interpolation problems, as well as the computation of the distance of a function f in L to H . At about the sametime as Sarason's work, V. M."

Metric Constrained Interpolation, Commutant Lifting and Systems

Metric Constrained Interpolation, Commutant Lifting and Systems PDF Author: C. Foias
Publisher: Birkhäuser
ISBN: 3034887914
Category : Mathematics
Languages : en
Pages : 587

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Book Description
This book presents a unified approach for solving both stationary and nonstationary interpolation problems, in finite or infinite dimensions, based on the commutant lifting theorem from operator theory and the state space method from mathematical system theory. Initially the authors planned a number of papers treating nonstationary interpolation problems of Nevanlinna-Pick and Nehari type by reducing these nonstationary problems to stationary ones for operator-valued functions with operator arguments and using classical commutant lifting techniques. This reduction method required us to review and further develop the classical results for the stationary problems in this more general framework. Here the system theory turned out to be very useful for setting up the problems and for providing natural state space formulas for describing the solutions. In this way our work involved us in a much wider program than original planned. The final results of our efforts are presented here. The financial support in 1994 from the "NWO-stimulansprogramma" for the Thomas Stieltjes Institute for Mathematics in the Netherlands enabled us to start the research which lead to the present book. We also gratefully acknowledge the support from our home institutions: Indiana University at Bloomington, Purdue University at West Lafayette, Tel-Aviv University, and the Vrije Universiteit at Amsterdam. We warmly thank Dr. A.L. Sakhnovich for his carefully reading of a large part of the manuscript. Finally, Sharon Wise prepared very efficiently and with great care the troff file of this manuscript; we are grateful for her excellent typing.

Interpolation, Schur Functions and Moment Problems

Interpolation, Schur Functions and Moment Problems PDF Author: Daniel Alpay
Publisher: Springer Science & Business Media
ISBN: 3764375477
Category : Mathematics
Languages : en
Pages : 310

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Book Description
Schur analysis originated with an 1917 article which associated to a function, which is analytic and contractive in the open unit disk, a sequence, finite or infinite, of numbers in the open unit disk, called Schur coefficients, often named reflection coefficients in signal processing. This volume comprises seven essays dedicated to the analysis of Schur and Carathéodory functions and to the solutions of problems for these classes.

Operator Algebras, Operator Theory and Applications

Operator Algebras, Operator Theory and Applications PDF Author: J. J. Grobler
Publisher: Springer Science & Business Media
ISBN: 3034601743
Category : Mathematics
Languages : en
Pages : 301

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Book Description
This volume contains the proceedings of the eighteenth International Workshop on Operator Theory and Applications (IWOTA), hosted by the Unit for Business Mathematics and Informatics of North-West University, Potchefstroom, South Africa from July 3 to 6, 2007. The conference (as well as these proceedings) was dedicated to Professors Joseph A. Ball and Marinus M. Kaashoek on the occasion of their 60th and 70th birthdays, respectively. This conference had a particular focus on Von Neumann algebras at the interface of operator theory with functional analysis and on applications of operator theory to differential equations.

Operator Theory and Interpolation

Operator Theory and Interpolation PDF Author: Hari Bercovic
Publisher: Birkhäuser
ISBN: 3034884222
Category : Mathematics
Languages : en
Pages : 311

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Book Description
A collection of articles emphasizing modern interpolation theory, a topic which has seen much progress in recent years. These ideas and problems in operator theory, often arising from systems and control theories, bring the reader to the forefront of current research in this area.

Classical Control Using H-Infinity Methods

Classical Control Using H-Infinity Methods PDF Author: J. William Helton
Publisher: SIAM
ISBN: 0898714192
Category : Technology & Engineering
Languages : en
Pages : 282

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Book Description
This versatile book teaches control system design using H-Infinity techniques that are simple and compatible with classical control, yet powerful enough to quickly allow the solution of physically meaningful problems. The authors begin by teaching how to formulate control system design problems as mathematical optimization problems and then discuss the theory and numerics for these optimization problems. Their approach is simple and direct, and since the book is modular, the parts on theory can be read independently of the design parts and vice versa, allowing readers to enjoy the book on many levels. Until now, there has not been a publication suitable for teaching the topic at the undergraduate level. This book fills that gap by teaching control system design using H^\infty techniques at a level within reach of the typical engineering and mathematics student. It also contains a readable account of recent developments and mathematical connections.

Linear Systems and Control

Linear Systems and Control PDF Author: Martin J. Corless
Publisher: CRC Press
ISBN: 9780203911372
Category : Mathematics
Languages : en
Pages : 368

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Book Description
Based largely on state space models, this text/reference utilizes fundamental linear algebra and operator techniques to develop classical and modern results in linear systems analysis and control design. It presents stability and performance results for linear systems, provides a geometric perspective on controllability and observability, and develops state space realizations of transfer functions. It also studies stabilizability and detectability, constructs state feedback controllers and asymptotic state estimators, covers the linear quadratic regulator problem in detail, introduces H-infinity control, and presents results on Hamiltonian matrices and Riccati equations.

Recent Advances in Operator Theory and Related Topics

Recent Advances in Operator Theory and Related Topics PDF Author: Laszlo Kerchy
Publisher: Birkhäuser
ISBN: 3034883749
Category : Mathematics
Languages : en
Pages : 719

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Book Description
These 35 refereed articles report on recent and original results in various areas of operator theory and connected fields, many of them strongly related to contributions of Sz.-Nagy. The scientific part of the book is preceeded by fifty pages of biographical material, including several photos.

Systems, Approximation, Singular Integral Operators, and Related Topics

Systems, Approximation, Singular Integral Operators, and Related Topics PDF Author: Alexander A. Borichev
Publisher: Birkhäuser
ISBN: 3034883625
Category : Computers
Languages : en
Pages : 536

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Book Description
This book is devoted to some topical problems and applications of operator theory and its interplay with modern complex analysis. It consists of 20 selected survey papers that represent updated (mainly plenary) addresses to the IWOTA 2000 conference held at Bordeaux from June 13 to 16, 2000. The main subjects of the volume include: - spectral analysis of periodic differential operators and delay equations, stabilizing controllers, Fourier multipliers; - multivariable operator theory, model theory, commutant lifting theorems, coisometric realizations; - Hankel operators and forms; - operator algebras; - the Bellman function approach in singular integrals and harmonic analysis, singular integral operators and integral representations; - approximation in holomorphic spaces. These subjects are unified by the common "operator theoretic approach" and the systematic use of modern function theory techniques.

Operator Extensions, Interpolation of Functions and Related Topics

Operator Extensions, Interpolation of Functions and Related Topics PDF Author: A. Gheondea
Publisher: Birkhäuser
ISBN: 303488575X
Category : Science
Languages : en
Pages : 225

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Book Description
Since 1976 the Institute of Mathematics of the Romanian Academy (formerly the Department of Mathematics of INCREST) and the Faculty of Mathematics (formerly the Faculty of Sciences) of the University ofTimi~oara have organized several Con ferences on Operator Theory. These Conferences were held yearly in Timi~oara (or in Timi~oara and Herculane) and beginning with 1985 they were held in Bucharest (1985,1986), in Timi~oara (1988) and in Predeal (1990). At the beginning, these Conferences answered the need of a part of the Romanian Mathematical Community ofexploring other forms of survival, after the dissolution of the Institute of Mathematics in 1975. Soon, these meetings evolved to International Conferences with a broad participation and where important results in Operator Theory and Operator Algebras and their interplay with Complex Function Theory, Differential Equations, Mathematical Physics, System Theory, etc. were presented. The 14th Conference on Operator Theory was held between June 1st and June 5th 1992, at the University ofTimi~oara. It was partially supported by the Institute of Mathematics of the Romanian Academy and by the Faculty of Mathematics of the University ofTimi~oara. Another important contribution towards covering the costs of this meeting came from The Soros Foundation for an Open Society. Without this generous help the organizing of this event would be impossible. Since 1980, the Proceedings of OT Conferences were published by Birkhauser Verlag in the series Operator Theory: Advances and Applications. The abstracts of the talks were collected in the Conference Report, published by the University of Timi~oara.