Linear and Quasi-linear Evolution Equations in Hilbert Spaces Pascal Cherrier Albert Milani Graduate Studies in Mathematics Volume 1,33 American Mathematical Society Linear and Quasi-linear Evolution Equations in Hilbert Spaces Linear and Quasi-linear Evolution Equations in Hilbert Spaces Pascal Cherrier Albert Milani Graduate Studies in Mathematics Volume 135 American Mathematical Society Providence, Rhode Island EDITORIAL COMMITTEE David Cox (Chair) Daniel S. Freed Rafe Mazzeo Gigliola Staffilani 2010 Mathematics Subject Classification. Primary 35L15, 35L72, 35K15, 35K59, 35Q61, 35Q74. For additional information and updates on this book, visit www.ams.org/bookpages/gsm-135 Library of Congress Cataloging-in-Publication Data Cherrier, Pascal, 1950- Linear and quasi-linear evolution equations in Hilbert spaces / Pascal Cherrier, Albert Milani. p. cm. - (Graduate studies in mathematics ; v. 135) Includes bibliographical references and index. ISBN 978-0-8218-7576-6 (alk. paper) 1. Initial value problems. 2. Differential equations, Hyperbolic. 3. Evolution equations. 4. Hilbert space. I. Milani, A. (Albert) II. Title. III. Title: Linear and quasilinear evolution equations in Hilbert spaces. QA378.C44 2012 515'.733-dc23 2012002958 Copying and reprinting. Individual readers of this publication, and nonprofit libraries acting for them, are permitted to make fair use of the material, such as to copy a chapter for use in teaching or research. Permission is granted to quote brief passages from this publication in reviews, provided the customary acknowledgment of the source is given. Republication, systematic copying, or multiple reproduction of any material in this publication is permitted only under license from the American Mathematical Society. Requests for such permission should be addressed to the Acquisitions Department, American Mathematical Society, 201 Charles Street, Providence, Rhode Island 02904-2294 USA. Requests can also be made by e-mail to reprint-permissionmams. org. © 2012 by the American Mathematical Society. All rights reserved. The American Mathematical Society retains all rights except those granted to the United States Government. Printed in the United States of America. Q The paper used in this book is acid-free and falls within the guidelines established to ensure permanence and durability. Visit the AMS home page at http : //www. ams. org/ 10987654321 171615141312 We dedicate this work to our wives, Annick and Claudia, whose love and support has sustained us throughout its redaction. We bow with respect to the memory of our Teachers, Thierry AuBIN and Tosio KA'ro, who have been a continuous source of inspiration and dedication. Magna non sine Difficultate Contents Preface ix Chapter 1. Functional Framework 1 §1.1. Basic Notation 1 §1.2. Functional Analysis Results 4 §1.3. Holder Spaces §1.4. Lebesgue Spaces §1.5. Sobolev Spaces §1.6. Orthogonal Bases in H'(R N) §1.7. Sobolev Spaces Involving Time Chapter 2. Linear Equations §2.1. Introduction §2.2. The Hyperbolic Cauchy Problem §2.3. Proof of Theorem 2.2.1 §2.4. Weak Solutions §2.5. The Parabolic Cauchy Problem Chapter 3. Quasi-linear Equations 119 §3.1. Introduction 119 §3.2. The Hyperbolic Cauchy Problem 122 §3.3. Proof of Theorem 3.2.1 131 §3.4. The Parabolic Cauchy Problem 145 vii Contents Chapter 4. Global Existence 153 §4.1. Introduction 153 §4.2. Life Span of Solutions 155 §4.3. Non Dissipative Finite Time Blow-Up 159 §4.4. Almost Global Existence 171 §4.5. Global Existence for Dissipative Equations 175 §4.6. The Parabolic Problem 214 Chapter 5. Asymptotic Behavior 233 §5.1. Introduction 233 §5.2. Convergence uhyp(t) -} usta 234 Convergence upar (t) -} §5.3. usta 241 §5.4. Stability Estimates 244 §5.5. The Diffusion Phenomenon 278 Chapter 6. Singular Convergence 293 §6.1. Introduction 293 §6.2. An Example from ODEs 295 §6.3. Uniformly Local and Global Existence 301 §6.4. Singular Perturbation 305 §6.5. Almost Global Existence 326 Chapter 7. Maxwell and von Karman Equations 335 §7.1. Maxwell's Equations 335 §7.2. von Karman's Equations 343 List of Function Spaces 361 Bibliography 365 Index 375 Preface 1. In these notes we develop a theory of strong solutions to linear evolution equations of the type (0.0.1) 6 utt + a ut - aij (t, x) 3 & u = f (t, x) , and their quasi-linear counterpart (0.0.2) 6 utt + a ut - aij (t, x, u, ut, VU) 3Z3ju = f (t, x) In (0.0.1) and (0.0.2), 6 and a are non-negative parameters; u = u(t, x), t > 0, x E RN, and summation over repeated indices i, j, 1 < i, j < N, is understood. In addition, and in a sense to be made more precise, the quadratic form RN E) aij (.. ) i j is positive definite. We distinguish the following three cases. (1) e > 0 and v = 0. Then, (0.0.1) and (0.0.2) are hyperbolic equations; in particular, when 6 = 1, they reduce to (0-0-3) utt - aij o9jo9ju = f , and when aij ( ) = S2j (the so-called Kronecker S, defined by 82j = 0 if i =,4 j, and Szj = 1 if i = j), (0.0.3) further reduces to the classical wave equation (0.0.4) utt - D u = f . (2) 6 = 0 and v > 0. Then, (0.0.1) and (0.0.2) are parabolic equations; in particular, when a = 1, they reduce to ut-az;aza,u=f, (0.0.5) ix