Boundary Value Problems, Weyl Functions, and Differential Operators
Boundary Value Problems, Weyl Functions, and Differential Operators

Author: Jussi Behrndt

Publisher: Springer Nature

Published: 2020-01-03

Total Pages: 772

ISBN-13: 3030367142

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This open access book presents a comprehensive survey of modern operator techniques for boundary value problems and spectral theory, employing abstract boundary mappings and Weyl functions. It includes self-contained treatments of the extension theory of symmetric operators and relations, spectral characterizations of selfadjoint operators in terms of the analytic properties of Weyl functions, form methods for semibounded operators, and functional analytic models for reproducing kernel Hilbert spaces. Further, it illustrates these abstract methods for various applications, including Sturm-Liouville operators, canonical systems of differential equations, and multidimensional Schrödinger operators, where the abstract Weyl function appears as either the classical Titchmarsh-Weyl coefficient or the Dirichlet-to-Neumann map. The book is a valuable reference text for researchers in the areas of differential equations, functional analysis, mathematical physics, and system theory. Moreover, thanks to its detailed exposition of the theory, it is also accessible and useful for advanced students and researchers in other branches of natural sciences and engineering.

Understanding Boundary Value Problems, Weyl Functions and Differential Operators: Volume 3
Understanding Boundary Value Problems, Weyl Functions and Differential Operators: Volume 3

Author: Williams Gerald

Publisher: Murphy & Moore Publishing

Published: 2021-11-16

Total Pages: 275

ISBN-13: 9781639875498

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Boundary value problems are differential equations with a set of additional constraints, called the boundary conditions. A solution which satisfies the boundary conditions is a solution to the boundary value problem and the differential equation. The Weyl distance function behaves in some ways like the distance function of a metric space. It takes values in a group of reflections, instead of taking values in the positive real numbers. This group of reflections is called the Weyl group. A differential operator is a function of the differentiation operator, also known as the derivative. Differentiation can be considered as an abstract operation that accepts a function and returns another function. This book provides significant information of this discipline to help develop a good understanding of boundary value problems, Weyl functions, differential operators and related fields. It presents this complex subject in the most comprehensible and easy to understand language. Constant effort has been made in this book, using case studies and examples, to make the understanding of these difficult concepts of mathematics as easy and informative as possible to the readers.

Understanding Boundary Value Problems, Weyl Functions and Differential Operators: Volume 1
Understanding Boundary Value Problems, Weyl Functions and Differential Operators: Volume 1

Author: Williams Gerald

Publisher: Murphy & Moore Publishing

Published: 2021-11-16

Total Pages: 233

ISBN-13: 9781639875474

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Boundary value problems are differential equations with a set of additional constraints, called the boundary conditions. A solution which satisfies the boundary conditions is a solution to the boundary value problem and the differential equation. The Weyl distance function behaves in some ways like the distance function of a metric space. It takes values in a group of reflections, instead of taking values in the positive real numbers. This group of reflections is called the Weyl group. A differential operator is a function of the differentiation operator, also known as the derivative. Differentiation can be considered as an abstract operation that accepts a function and returns another function. This book provides significant information of this discipline to help develop a good understanding of boundary value problems, Weyl functions, differential operators and related fields. It presents this complex subject in the most comprehensible and easy to understand language. Constant effort has been made in this book, using case studies and examples, to make the understanding of these difficult concepts of mathematics as easy and informative as possible to the readers.

Understanding Boundary Value Problems, Weyl Functions and Differential Operators: Volume 2
Understanding Boundary Value Problems, Weyl Functions and Differential Operators: Volume 2

Author: Williams Gerald

Publisher: Murphy & Moore Publishing

Published: 2021-11-16

Total Pages: 286

ISBN-13: 9781639875481

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Boundary value problems are differential equations with a set of additional constraints, called the boundary conditions. A solution which satisfies the boundary conditions is a solution to the boundary value problem and the differential equation. The Weyl distance function behaves in some ways like the distance function of a metric space. It takes values in a group of reflections, instead of taking values in the positive real numbers. This group of reflections is called the Weyl group. A differential operator is a function of the differentiation operator, also known as the derivative. Differentiation can be considered as an abstract operation that accepts a function and returns another function. This book provides significant information of this discipline to help develop a good understanding of boundary value problems, Weyl functions, differential operators and related fields. It presents this complex subject in the most comprehensible and easy to understand language. Constant effort has been made in this book, using case studies and examples, to make the understanding of these difficult concepts of mathematics as easy and informative as possible to the readers.

Operator Methods for Boundary Value Problems
Operator Methods for Boundary Value Problems

Author: Seppo Hassi

Publisher: Cambridge University Press

Published: 2012-10-11

Total Pages: 297

ISBN-13: 1139561316

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Presented in this volume are a number of new results concerning the extension theory and spectral theory of unbounded operators using the recent notions of boundary triplets and boundary relations. This approach relies on linear single-valued and multi-valued maps, isometric in a Krein space sense, and offers a basic framework for recent developments in system theory. Central to the theory are analytic tools such as Weyl functions, including Titchmarsh-Weyl m-functions and Dirichlet-to-Neumann maps. A wide range of topics is considered in this context from the abstract to the applied, including boundary value problems for ordinary and partial differential equations; infinite-dimensional perturbations; local point-interactions; boundary and passive control state/signal systems; extension theory of accretive, sectorial and symmetric operators; and Calkin's abstract boundary conditions. This accessible treatment of recent developments, written by leading researchers, will appeal to a broad range of researchers, students and professionals.

Boundary Value Problems with Global Projection Conditions
Boundary Value Problems with Global Projection Conditions

Author: Xiaochun Liu

Publisher: Birkhäuser

Published: 2018-10-30

Total Pages: 410

ISBN-13: 3319701142

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This book presents boundary value problems for arbitrary elliptic pseudo-differential operators on a smooth compact manifold with boundary. In this regard, every operator admits global projection boundary conditions, giving rise to analogues of Toeplitz operators in subspaces of Sobolev spaces on the boundary associated with pseudo-differential projections. The book describes how these operator classes form algebras, and establishes the concept for Boutet de Monvel’s calculus, as well as for operators on manifolds with edges, including the case of operators without the transmission property. Further, it shows how the calculus contains parametrices of elliptic elements. Lastly, the book describes natural connections to ellipticity of Atiyah-Patodi-Singer type for Dirac and other geometric operators, in particular spectral boundary conditions with Calderón-Seeley projections and the characterization of Cauchy data spaces.

Boundary Value Problems of Mathematical Physics
Boundary Value Problems of Mathematical Physics

Author: Ivar Stakgold

Publisher: SIAM

Published: 2000-06-30

Total Pages: 1156

ISBN-13: 0898714567

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For more than 30 years, this two-volume set has helped prepare graduate students to use partial differential equations and integral equations to handle significant problems arising in applied mathematics, engineering, and the physical sciences. Originally published in 1967, this graduate-level introduction is devoted to the mathematics needed for the modern approach to boundary value problems using Green's functions and using eigenvalue expansions. Now a part of SIAM's Classics series, these volumes contain a large number of concrete, interesting examples of boundary value problems for partial differential equations that cover a variety of applications that are still relevant today. For example, there is substantial treatment of the Helmholtz equation and scattering theory?subjects that play a central role in contemporary inverse problems in acoustics and electromagnetic theory.

Boundary Value Problems for Elliptic Systems
Boundary Value Problems for Elliptic Systems

Author: J. T. Wloka

Publisher: Cambridge University Press

Published: 1995-07-28

Total Pages: 659

ISBN-13: 0521430119

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The theory of boundary value problems for elliptic systems of partial differential equations has many applications in mathematics and the physical sciences. The aim of this book is to "algebraize" the index theory by means of pseudo-differential operators and new methods in the spectral theory of matrix polynomials. This latter theory provides important tools that will enable the student to work efficiently with the principal symbols of the elliptic and boundary operators on the boundary. Because many new methods and results are introduced and used throughout the book, all the theorems are proved in detail, and the methods are well illustrated through numerous examples and exercises. This book is ideal for use in graduate level courses on partial differential equations, elliptic systems, pseudo-differential operators, and matrix analysis.

The Weyl Operator and its Generalization
The Weyl Operator and its Generalization

Author: Leon Cohen

Publisher: Springer Science & Business Media

Published: 2012-12-13

Total Pages: 167

ISBN-13: 3034802943

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The discovery of quantum mechanics in the years 1925-1930 necessitated the consideration of associating ordinary functions with non-commuting operators. Methods were proposed by Born/Jordan, Kirkwood, and Weyl. Sometime later, Moyal saw the connection between the Weyl rule and the Wigner distribution, which had been proposed by Wigner in 1932 as a way of doing quantum statistical mechanics. The basic idea of associating functions with operators has since been generalized and developed to a high degree. It has found several application fields, including quantum mechanics, pseudo-differential operators, time-frequency analysis, quantum optics, wave propagation, differential equations, image processing, radar, and sonar. This book aims at bringing together the results from the above mentioned fields in a unified manner and showing the reader how the methods have been applied. A wide audience is addressed, particularly students and researchers who want to obtain an up-to-date working knowledge of the field. The mathematics is accessible to the uninitiated reader and is presented in a straightforward manner.

An Introduction to Nonlinear Boundary Value Problems
An Introduction to Nonlinear Boundary Value Problems

Author: Lakshmikantham

Publisher: Academic Press

Published: 1974-05-31

Total Pages: 399

ISBN-13: 0080956181

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A book on an advanced level that exposes the reader to the fascinating field of differential equations and provides a ready access to an up-to-date state of this art is of immense value. This book presents a variety of techniques that are employed in the theory of nonlinear boundary value problems. For example, the following are discussed: methods that involve differential inequalities; shooting and angular function techniques; functional analytic approaches; topological methods.