Foundations of Abstract Analysis Jewgeni H. Dshalalow Foundations of Abstract Analysis Second Edition Jewgeni H. Dshalalow Mathematical Sciences Florida Institute of Technology Melbourne 32901 Florida USA ISBN978-1-4614-5961-3 ISBN9 78-1-4614-5962-0 (eBook) DOI10.1007/978-1-4614-5962-0 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2012951666 Mathematics Subject Classification (2010): 54-01, 28A05, 28A10, 28A12, 28A20, 28A25, 28A33, 28A35, 26-XX, 26-01 2nd Ed of a book previously published by Chapman and Hall/CRC Press in 2000, Real Analysis: An Introduction to the Theory of Real Functions and Integration © Springer Science+Business Media, LLC 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) To Irina Preface This is the first of a two book series written for beginning graduate- level real analysis students and it is focused on essentials of set theo- ry, topology, and measure theory. The word “essentials” is often as- sociated with lecture notes, but this is exactly opposite to my inten- tion. While there are quite a few fine abstract analysis books, they are difficult to read, and an enthusiastic reader needs more time and effort to master the subject, as opposed to elementary level books that only in part address the needs of forthcoming mathematics and advancedengineeringcourses. That is why this book offers a thorough and yet rigorous treat- ment of key analysis subjects in abstract spaces by providing the reader with copious illustrations, examples, and exercises with se- lected solutions. Some difficult to understand topics are preceded by detaileddiscussions andblueprints, so that thereaderwill not get lost or intimidated in a long chain of proofs and notions. Furthermore, at the end of each section there is a summaryof new terms and notation in the chronological order in which they appeared in the text. This should be helpful and relieve students of the potential overload of new words, definitions, and concepts. So, there is an increased likeli- hood of success byusingthis text in a course or bymeans of individ- ual self-study. Myprevious text, Real Analysis, published byChapman and Hall in 2000, was the first effort to createthiskindofbook.However,this book only partially accomplished the goal I was striving to achieve. To fully realize that goal, it was necessary to write a new and ex- panded edition, including more topics and details, and it had to be produced as two books. The companion book, Advances in Abstract Analysis and Applications, includes further topics in topology and vii viii Preface measure theory, which justifies and rewards the reader for investing thetimespent on“essentials.” As mathematical education has become increasingly more fo- cused on applications and less on theory, and in order to save them from extinction, academics have repurposed courses in set theory, to- pology, abstract algebra, and measureandintegrationas areal analy- sis course. At the same time, mathematical research, driven by seri- ous applications to other sciences, continued to require sound foun- dations. The pertinent precedents include physics, stochastic finance, mechanics, and now biology. There was even a time when some pro- ponents called real analysis “the single most important graduate courseinmathematics toprepareforacareerinoperations research.” Today, real analysis is still very much alive, although it has un- dergone some significant modifications. One of these changes is that contemporary real analysis books include various, sometimes exotic, applications ranging from partial differentials equations to wavelet analysis, probability, and even physics. While such connections might be justified, one has to ensure that this propensity to connect analysis with remote disciplines does not relax its very substance. Consequently, facinga challenge of two alternatives to yieldanover- sized or abridged book, a broad-spectrum project (under strong en- couragement from Springer) got bifurcated into two entirely differ- entlyfocusedtexts. Because real analysis, in its proper form, is likely to be the first abstract mathematics course that many students take, the associated topics should be taught in a strict order starting with basic set theory followed by point-set topology and then measure theory and integra- tion. Throughout my book I follow these principles. I strongly advo- cate the idea of introducing measure and integration in abstract spaces wasting no valuable time on Euclidean spaces. Consequently, Lebesgue measure and Lebesgue integral are reduced to mere illus- trations. The topology part, to be necessarily preceded by metric spaces, contains mostly fundamentals (such as bases, subbases, Hausdorff spaces, Tychonov product, and compactness). In partic- ular, old good sequential convergence is enough to proceed with rig- orous and comprehensive measure and integration (which accounts Preface ix to over 55% of my book). Such topics as filters and nets, locally compact Hausdorff spaces, Radon measures, and Hilbert spaces (measure-theoretic version) I consider relatively advanced and there- fore treat them in my forthcoming sequel to this book, along with various applications tostochasticanalysis. It is absolutely impossible to produce a sound text without building on the foundations of my predecessors' important scholar- ship. I am very grateful for the valuable remarks and suggestions, made to the present and earlier edition, by Gustave Choquet, Jerald Folland, Jordan Stoyanov, Jürgen Becker, Richard Syski, Jean Lasserre, Donald Konwinski, and Dean Spitzer. I am much indebted to Simon Smith, the creator of the EXP word processor, for his gen- erous and timelysupport. Mydeep appreciationalso goes toMs.Vaishali Damle,whois an extremely competent and efficient mathematics editor. Her constant help and patience was made available from the verybeginning of the project and receiving her feedback was one of the key benefits of writing the book. Finally, I want to thank the Springer copyeditor, Ms. Valerie Greco, who did an excellent job in polishing the final draft of my manuscript. Because books are often written at home, I would be remiss in not ending with profound gratitude to my wife, Irina, who createdanenvironment conducivetowritingthis book. J.H.Dshalalow Melbourne,Florida
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