mm14_meissfm-a.qxp 9/24/2007 4:34 PM Page 1 Differential Dynamical Systems mm14_meissfm-a.qxp 9/24/2007 4:34 PM Page 2 Mathematical Modeling Editor-in-Chief and Computation Richard Haberman Southern Methodist About the Series University The SIAM series on Mathematical Modeling and Computation draws attention to the wide range of important problems in the physical and life sciences and Editorial Board engineering that are addressed by mathematical modeling and computation; promotes the interdisciplinary culture required to meet these large-scale challenges; Alejandro Aceves and encourages the education of the next generation of applied and computational University of New mathematicians, physical and life scientists, and engineers. Mexico The books cover analytical and computational techniques, describe significant mathematical developments, and introduce modern scientific and engineering Andrea Bertozzi applications. The series will publish lecture notes and texts for advanced University of California, undergraduate- or graduate-level courses in physical applied mathematics, Los Angeles biomathematics, and mathematical modeling, and volumes of interest to a wide segment of the community of applied mathematicians, computational scientists, and engineers. Bard Ermentrout University of Pittsburgh Appropriate subject areas for future books in the series include fluids, dynamical systems and chaos, mathematical biology, neuroscience, mathematical physiology, epidemiology, morphogenesis, biomedical engineering, reaction-diffusion in Thomas Erneux chemistry, nonlinear science, interfacial problems, solidification, combustion, Université Libre de transport theory, solid mechanics, nonlinear vibrations, electromagnetic theory, Brussels nonlinear optics, wave propagation, coherent structures, scattering theory, earth science, solid-state physics, and plasma physics. Bernie Matkowsky Northwestern University James D. Meiss, Differential Dynamical Systems E. van Groesen and Jaap Molenaar, Continuum Modeling in the Physical Sciences Robert M. Miura Gerda de Vries, Thomas Hillen, Mark Lewis, Johannes Müller, and Birgitt New Jersey Institute Schönfisch, A Course in Mathematical Biology: Quantitative Modeling with of Technology Mathematical and Computational Methods Ivan Markovsky, Jan C. Willems, Sabine Van Huffel, and Bart De Moor, Exact and Approximate Modeling of Linear Systems: A Behavioral Approach Michael Tabor University of Arizona R. M. M. Mattheij, S. W. Rienstra, and J. H. M. ten Thije Boonkkamp, Partial Differential Equations: Modeling, Analysis, Computation Johnny T. Ottesen, Mette S. Olufsen, and Jesper K. Larsen, Applied Mathematical Models in Human Physiology Ingemar Kaj, Stochastic Modeling in Broadband Communications Systems Peter Salamon, Paolo Sibani, and Richard Frost, Facts, Conjectures, and Improvements for Simulated Annealing Lyn C. Thomas, David B. Edelman, and Jonathan N. Crook, Credit Scoring and Its Applications Frank Natterer and Frank Wübbeling, Mathematical Methods in Image Reconstruction Per Christian Hansen, Rank-Deficient and Discrete Ill-Posed Problems: Numerical Aspects of Linear Inversion Michael Griebel, Thomas Dornseifer, and Tilman Neunhoeffer, Numerical Simulation in Fluid Dynamics: A Practical Introduction Khosrow Chadan, David Colton, Lassi Päivärinta, and William Rundell, An Introduction to Inverse Scattering and Inverse Spectral Problems Charles K. Chui, Wavelets: A Mathematical Tool for Signal Analysis mm14_meissfm-a.qxp 9/24/2007 4:34 PM Page 3 Differential Dynamical Systems James D. Meiss University of Colorado Boulder, Colorado Society for Industrial and Applied Mathematics Philadelphia mm14_meissfm-a.qxp 9/24/2007 4:34 PM Page 4 Copyright © 2007 by the Society for Industrial and Applied Mathematics. 10 9 8 7 6 5 4 3 2 1 All rights reserved. Printed in the United States of America. No part of this book may be reproduced, stored, or transmitted in any manner without the written permission of the publisher. For information, write to the Society for Industrial and Applied Mathematics, 3600 Market Street, 6th floor, Philadelphia, PA 19104-2688 USA. Trademarked names may be used in this book without the inclusion of a trademark symbol. These names are used in an editorial context only; no infringement of trademark is intended. Maple is a registered trademark of Waterloo Maple, Inc. Mathematica is a registered trademark of Wolfram Research, Inc. MATLAB is a registered trademark of The MathWorks, Inc. For MATLAB product information, please contact The MathWorks, Inc., 3 Apple Hill Drive, Natick, MA 01760-2098 USA, 508-647-7000, Fax: 508-647-7101, [email protected], www.mathworks.com. Library of Congress Cataloging-in-Publication Data Meiss, J. D. Differential dynamical systems / James D. Meiss. p. cm. — (Mathematical modeling and computation ; 14) Includes bibliographical references and index. ISBN 978-0-898716-35-1 (alk. paper) 1. Differential dynamical systems—Mathematical models. I. Title. QA614.8.M45 2007 515’.39—dc22 2007061747 is a registered trademark. mm14_meissfm-a.qxp 9/24/2007 4:34 PM Page 5 To Don and Peggy Meiss for teaching me to explore, and to Mary Sue Moore for always believing that I would discover. (cid:2) mm14_meissfm-a.qxp 9/24/2007 4:34 PM Page 6 Contents ListofFigures xi Preface xvii Acknowledgments xxi 1 Introduction 1 1.1 Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 WhatAreDifferentialEquations? . . . . . . . . . . . . . . . . . . . . 2 1.3 One-DimensionalDynamics. . . . . . . . . . . . . . . . . . . . . . . 5 1.4 Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 PopulationDynamics . . . . . . . . . . . . . . . . . . . . . . . . . . 8 MechanicalSystems . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 OscillatingCircuits . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 FluidMixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.5 Two-DimensionalDynamics . . . . . . . . . . . . . . . . . . . . . . 14 Nullclines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 PhaseCurves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.6 TheLorenzModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1.7 QuadraticODEs: TheSimplestChaoticSystems . . . . . . . . . . . . 21 1.8 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2 LinearSystems 29 2.1 MatrixODEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 EigenvaluesandEigenvectors . . . . . . . . . . . . . . . . . . . . . . 30 Diagonalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.2 Two-DimensionalLinearSystems . . . . . . . . . . . . . . . . . . . . 35 2.3 ExponentialsofOperators . . . . . . . . . . . . . . . . . . . . . . . . 40 2.4 FundamentalSolutionTheorem . . . . . . . . . . . . . . . . . . . . . 45 2.5 ComplexEigenvalues . . . . . . . . . . . . . . . . . . . . . . . . . . 48 2.6 MultipleEigenvalues . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Semisimple-NilpotentDecomposition. . . . . . . . . . . . . . . . . . 51 TheExponential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 AlternativeMethods . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 vii viii Contents 2.7 LinearStability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 2.8 NonautonomousLinearSystemsandFloquetTheory. . . . . . . . . . 61 2.9 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 3 ExistenceandUniqueness 73 3.1 SetandTopologicalPreliminaries . . . . . . . . . . . . . . . . . . . . 73 Convergence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 UniformConvergence . . . . . . . . . . . . . . . . . . . . . . . . . . 75 3.2 FunctionSpacePreliminaries . . . . . . . . . . . . . . . . . . . . . . 76 MetricSpaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 ContractionMaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 LipschitzFunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 3.3 ExistenceandUniquenessTheorem . . . . . . . . . . . . . . . . . . . 84 3.4 DependenceonInitialConditionsandParameters . . . . . . . . . . . 92 3.5 MaximalIntervalofExistence. . . . . . . . . . . . . . . . . . . . . . 98 3.6 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 4 DynamicalSystems 105 4.1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 4.2 Flows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 4.3 GlobalExistenceofSolutions . . . . . . . . . . . . . . . . . . . . . . 109 4.4 Linearization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 4.5 Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 4.6 LyapunovFunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 4.7 TopologicalConjugacyandEquivalence . . . . . . . . . . . . . . . . 130 4.8 Hartman–GrobmanTheorem . . . . . . . . . . . . . . . . . . . . . . 138 4.9 Omega-LimitSets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 4.10 AttractorsandBasins . . . . . . . . . . . . . . . . . . . . . . . . . . 148 4.11 StabilityofPeriodicOrbits . . . . . . . . . . . . . . . . . . . . . . . 152 4.12 PoincaréMaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 4.13 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 5 InvariantManifolds 165 5.1 StableandUnstableSets . . . . . . . . . . . . . . . . . . . . . . . . . 165 5.2 HeteroclinicOrbits. . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 5.3 StableManifolds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 5.4 LocalStableManifoldTheorem . . . . . . . . . . . . . . . . . . . . . 173 5.5 GlobalStableManifolds . . . . . . . . . . . . . . . . . . . . . . . . . 181 5.6 CenterManifolds . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 5.7 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 6 ThePhasePlane 197 6.1 NonhyperbolicEquilibriainthePlane . . . . . . . . . . . . . . . . . 197 6.2 TwoZeroEigenvaluesandNonhyperbolicNodes . . . . . . . . . . . 198 6.3 ImaginaryEigenvalues: TopologicalCenters . . . . . . . . . . . . . . 203 6.4 SymmetriesandReversors . . . . . . . . . . . . . . . . . . . . . . . 211 Contents ix 6.5 IndexTheory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 HigherDimensions: TheDegree . . . . . . . . . . . . . . . . . . . . 217 6.6 Poincaré–BendixsonTheorem . . . . . . . . . . . . . . . . . . . . . . 219 6.7 LiénardSystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 6.8 BehavioratInfinity: ThePoincaréSphere . . . . . . . . . . . . . . . 229 6.9 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 7 ChaoticDynamics 243 7.1 Chaos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 7.2 LyapunovExponents . . . . . . . . . . . . . . . . . . . . . . . . . . 248 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 PropertiesofLyapunovExponents . . . . . . . . . . . . . . . . . . . 252 ComputingExponents . . . . . . . . . . . . . . . . . . . . . . . . . . 255 7.3 StrangeAttractors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 HausdorffDimension . . . . . . . . . . . . . . . . . . . . . . . . . . 260 Strange,NonchaoticAttractors . . . . . . . . . . . . . . . . . . . . . 262 7.4 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 8 BifurcationTheory 267 8.1 BifurcationsofEquilibria . . . . . . . . . . . . . . . . . . . . . . . . 267 8.2 PreservationofEquilibria . . . . . . . . . . . . . . . . . . . . . . . . 271 8.3 UnfoldingVectorFields . . . . . . . . . . . . . . . . . . . . . . . . . 273 UnfoldingTwo-DimensionalLinearFlows . . . . . . . . . . . . . . . 275 8.4 Saddle-NodeBifurcationinOneDimension . . . . . . . . . . . . . . 278 8.5 NormalForms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281 HomologicalOperator . . . . . . . . . . . . . . . . . . . . . . . . . . 282 MatrixRepresentation . . . . . . . . . . . . . . . . . . . . . . . . . . 285 Higher-OrderNormalForms . . . . . . . . . . . . . . . . . . . . . . 287 8.6 Saddle-NodeBifurcationinRn . . . . . . . . . . . . . . . . . . . . . 290 Transversality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 CenterManifoldMethods . . . . . . . . . . . . . . . . . . . . . . . . 293 8.7 DegenerateSaddle-NodeBifurcations . . . . . . . . . . . . . . . . . 295 8.8 Andronov–HopfBifurcation . . . . . . . . . . . . . . . . . . . . . . . 296 8.9 TheCuspBifurcation . . . . . . . . . . . . . . . . . . . . . . . . . . 301 8.10 Takens–BogdanovBifurcation . . . . . . . . . . . . . . . . . . . . . 304 8.11 HomoclinicBifurcations. . . . . . . . . . . . . . . . . . . . . . . . . 306 FragilityofHeteroclinicOrbits . . . . . . . . . . . . . . . . . . . . . 306 GenericHomoclinicBifurcationsinR2 . . . . . . . . . . . . . . . . . 309 8.12 Melnikov’sMethod . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 8.13 Melnikov’sMethodforNonautonomousPerturbations . . . . . . . . . 314 8.14 ShilnikovBifurcation . . . . . . . . . . . . . . . . . . . . . . . . . . 322 8.15 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 9 HamiltonianDynamics 333 9.1 ConservativeDynamics . . . . . . . . . . . . . . . . . . . . . . . . . 333 9.2 Volume-PreservingFlows . . . . . . . . . . . . . . . . . . . . . . . . 335