TY - BOOK AU - Hydon,Peter E. ED - Cambridge University Press. TI - Symmetry methods for differential equations: a beginner's guide T2 - Cambridge texts in applied mathematics SN - 0521497035 AV - QC20.7.D5 H93 2000 PY - 2000/// CY - Cambridge, New York PB - Cambridge University Press KW - Differential equations KW - Numerical solutions KW - Symmetry KW - Mathematical physics N1 - Includes bibliographical references (pages 209-210) and index; Preface ; Acknowledgements ; 1 Introduction to Symmetries 1; 1.1 Symmetries of Planar Objects 1; 1.2 Symmetries of the Simplest ODE 5; 1.3 The Symmetry Condition for First-Order ODEs 8; 1.4 Lie Symmetries Solve First-Order ODEs 11; 2 Lie Symmetries of First-Order ODEs 15; 2.1 The Action of Lie Symmetries on the Plane 15; 2.2 Canonical Coordinates 22; 2.3 How to Solve ODEs with Lie Symmetries 26; 2.4 The Linearized Symmetry Condition 30; 2.5 Symmetries and Standard Methods 34; 2.6 The Infinitesimal Generator 38; 3 How to Find Lie Point Symmetries of ODEs 43; 3.1 The Symmetry Condition 43; 3.2 The Determining Equations for Lie Point Symmetries 46; 3.3 Linear ODEs 52; 3.4 Justification of the Symmetry Condition 54; 4 How to Use a One-Parameter Lie Group 58; 4.1 Reduction of Order by Using Canonical Coordinates 58; 4.2 Variational Symmetries 63; 4.3 Invariant Solutions 68; 5 Lie Symmetries with Several Parameters 74; 5.1 Differential Invariants and Reduction of Order 74; 5.2 The Lie Algebra of Point Symmetry Generators 79; 5.3 Stepwise Integration of ODEs 89; 6 Solution of ODEs with Multiparameter Lie Groups 93; 6.1 The Basic Method: Exploiting Solvability 93; 6.2 New Symmetries Obtained During Reduction 99; 6.3 Integration of Third-Order ODEs with sl(2) 101; 7 Techniques Based on First Integrals 108; 7.1 First Integrals Derived from Symmetries 108; 7.2 Contact Symmetries and Dynamical Symmetries 116; 7.3 Integrating Factors 122; 7.4 Systems of ODEs 128; 8 How to Obtain Lie Point Symmetries of PDEs 136; 8.1 Scalar PDEs with Two Dependent Variables 136; 8.2 The Linearized Symmetry Condition for General PDEs 146; 8.3 Finding Symmetries by Computer Algebra 149; 9 Methods for Obtaining Exact Solutions of PDEs 155; 9.1 Group-Invariant Solutions 155; 9.2 New Solutions from Known Ones 162; 9.3 Nonclassical Symmetries 166; 10 Classification of Invariant Solutions 173; 10.1 Equivalence of Invariant Solutions 173; 10.2 How to Classify Symmetry Generators 176; 10.3 Optimal Systems of Invariant Solutions 182; 11 Discrete Symmetries 187; 11.1 Some Uses of Discrete Symmetries 187; 11.2 How to Obtain Discrete Symmetries from Lie Symmetries 188; 11.3 Classification of Discrete Symmetries 191; 11.4 Examples 195; Hints and Partial Solutions to Some Exercises 201; Bibliography 209; Index 211 ER -