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1989 | Buch

Symmetries and Differential Equations

verfasst von: George W. Bluman, Sukeyuki Kumei

Verlag: Springer New York

Buchreihe : Applied Mathematical Sciences

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Über dieses Buch

A major portion of this book discusses work which has appeared since the publication of the book Similarity Methods for Differential Equations, Springer-Verlag, 1974, by the first author and J.D. Cole. The present book also includes a thorough and comprehensive treatment of Lie groups of tranformations and their various uses for solving ordinary and partial differential equations. No knowledge of group theory is assumed. Emphasis is placed on explicit computational algorithms to discover symmetries admitted by differential equations and to construct solutions resulting from symmetries. This book should be particularly suitable for physicists, applied mathematicians, and engineers. Almost all of the examples are taken from physical and engineering problems including those concerned with heat conduction, wave propagation, and fluid flows. A preliminary version was used as lecture notes for a two-semester course taught by the first author at the University of British Columbia in 1987-88 to graduate and senior undergraduate students in applied mathematics and physics. Chapters 1 to 4 encompass basic material. More specialized topics are covered in Chapters 5 to 7.

Inhaltsverzeichnis

Frontmatter
Introduction
Abstract
In the latter part of the 19th century Sophus Lie introduced the notion of continuous groups, now known as Lie groups, in order to unify and extend various specialized solution methods for ordinary differential equations. Lie was inspired by lectures of Sylow given at Christiania (present-day Oslo) on Galois theory and Abel’s related works. [In 1881 Sylow and Lie collaborated in a careful editing of Abel’s complete works.] Lie showed that the order of an ordinary differential equation can be reduced by one, constructively, if it is invariant under a one-parameter Lie group of point transformations.
George W. Bluman, Sukeyuki Kumei
1. Dimensional Analysis, Modelling, and Invariance
Abstract
In this chapter we introduce the ideas of invariance concretely through a thorough treatment of dimensional analysis. We show how dimensional analysis is connected to modelling and the construction of solutions obtained through invariance for boundary value problems for partial differential equations.
George W. Bluman, Sukeyuki Kumei
3. Ordinary Differential Equations
Abstract
In this chapter we apply infinitesimal transformations (Lie groups of transformations) to the study of an nth order ordinary differential equation (ODE) written in a solved form
$${y_n} = f\left( {x,y,{y_1}, \ldots {y_n} - 1} \right),$$
(3.1)
where
$${y_k} = \frac{{{d^k}y}}{{d{x^k}}},k = 1,2,...,n.$$
ODE (3.1) defines a surface in (x,y,y1,...,y n )-space.
George W. Bluman, Sukeyuki Kumei
4. Partial Differential Equations
Abstract
In this chapter we apply infinitesimal transformations to the construction of solutions of partial differential equations (PDE’s). We will consider scalar (single) PDE’s and systems of PDE’s.
George W. Bluman, Sukeyuki Kumei
5. Noether’s Theorem and Lie-Bäcklund Symmetries
Abstract
In the preceding chapters we established the algorithm to determine Lie groups of point transformations of differential equations and developed methods to solve differential equations using such symmetries. In this chapter we study one of the most important applications of symmetries to physical problems, namely, the construction of conservation laws.
George W. Bluman, Sukeyuki Kumei
6. Construction of Mappings Relating Differential Equations
Abstract
In previous chapters we have considered the construction and use of infinitesimal transformations which leave a given differential equation invariant. These transformations map any solution of the given DE into another solution of the same DE. We have used infinitesimal transformations to reduce the order of ODE’s and to construct invariant solutions and conservation laws for DE’s.
George W. Bluman, Sukeyuki Kumei
7. Potential Symmetries
Abstract
As defined previously, a symmetry group of a differential equation is a group which maps any solution of the differential equation to another solution of the differential equation. In previous chapters we considered symmetries defined by infinitesimal transformations whose infinitesimals depend on independent variables, dependent variables, and derivatives of dependent variables. Such symmetries are local symmetries since at any point x the infinitesimals are determined if u(x) is sufficiently smooth in some neighborhood of x. In Chapters 5 and 6, by enlarging the classes of local symmetries admitted by given differential equations from point symmetries to contact symmetries, and, still more generally, to Lie-Bäklund symmetries, we could find more conservation laws, construct mappings to related differential equations, and determine more invariant solutions.
George W. Bluman, Sukeyuki Kumei
Backmatter
Metadaten
Titel
Symmetries and Differential Equations
verfasst von
George W. Bluman
Sukeyuki Kumei
Copyright-Jahr
1989
Verlag
Springer New York
Electronic ISBN
978-1-4757-4307-4
Print ISBN
978-1-4757-4309-8
DOI
https://doi.org/10.1007/978-1-4757-4307-4