Infinite Groups In recent times, group theory has found wider applications in various fields of algebra and math- ematics in general. But in order to apply this or that result, you need to know about it, and such results are often diffuse and difficult to locate, necessitating that readers construct an extended search through multiple monographs, articles, and papers. Such readers must wade through the morass of concepts and auxiliary statements that are needed to understand the desired results, while it is initially unclear which of them are really needed and which ones can be dispensed with. A further difficulty that one may encounter might be concerned with the form or language in which a given result is presented. For example, if someone knows the basics of group theory, but does not know the theory of representations, and a group theoretical result is formulated in the language of representation theory, then that person is faced with the problem of translating this result into the language with which they are familiar, etc. Infinite Groups: A Roadmap to Selected Classical Areas seeks to overcome this challenge. The book covers a broad swath of the theory of infinite groups, without giving proofs, but with all the concepts and auxiliary results necessary for understanding such results. In other words, this book is an extended directory, or a guide, to some of the more established areas of infinite groups. Features • An excellent resource for a subject formerly lacking an accessible and in-depth reference • Suitable for graduate students, PhD students, and researchers working in group theory • Introduces the reader to the most important methods, ideas, approaches, and constructions in infinite group theory. Taylor & Francis Taylor & Francis Group http://taylorandfrancis.com Infinite Groups A Roadmap to Selected Classical Areas Martyn R. Dixon University of Alabama, United States of America Leonid A. Kurdachenko Oles Honchar Dnipro National University, Ukraine Igor Ya. Subbotin National University, USA First edition published 2023 by CRC Press 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742 and by CRC Press 4 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN CRC Press is an imprint of Taylor & Francis Group, LLC © 2023 Martyn R. Dixon, Leonid A. Kurdachenko, Igor Ya. 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Taylor & Francis Taylor & Francis Group http://taylorandfrancis.com Contents Preface xi Authors xvii Chapter 1(cid:4) Important Subgroups 1 1.1 SOMEIMPORTANTSERIESINGROUPSANDSUBGROUPS DEFINEDBYTHESESERIES 4 1.2 CLASSESOFGROUPSDEFINEDBYSERIESOFSUBGROUPS 12 1.3 RADICABLEGROUPS 18 1.4 SOMETHINGFROMTHETHEORYOFMODULES 21 1.5 THE0-RANKANDp-RANKOFABELIANGROUPS 22 1.6 THEFRATTINISUBGROUPOFAGROUP 25 1.7 LINEARGROUPS 28 1.8 RESIDUALLYX-GROUPS 33 References for Chapter 1 41 Chapter 2(cid:4) Finitely Generated Groups 49 2.1 THEGENERALIZEDBURNSIDEPROBLEM 51 2.2 THEBURNSIDEPROBLEMFORGROUPSOFFINITEEXPONENT 52 2.3 THERESTRICTEDBURNSIDEPROBLEM 54 2.4 GROWTHFUNCTIONSONFINITELYGENERATEDGROUPS 55 2.5 FINITELYPRESENTEDGROUPS 58 2.6 GROUPSWITHTHEMAXIMALCONDITIONFORALLSUBGROUPS 61 References for Chapter 2 72 Chapter 3(cid:4) Finiteness Conditions 83 3.1 THEMINIMALCONDITIONONCERTAINSYSTEMSOF SUBGROUPS 83 vii viii (cid:4) Contents 3.2 THEMINIMALCONDITIONONNORMALSUBGROUPS 90 3.3 ARTINIANANDRELATEDMODULESOVERSOMEGROUPRINGS 93 3.4 MINIMAXGROUPS 102 3.5 THEWEAKMINIMALCONDITION 107 3.6 THEWEAKMAXIMALCONDITION 114 References for Chapter 3 117 Chapter 4(cid:4) Ranks of Groups 127 4.1 FINITESPECIALRANKANDFINITESECTIONp-RANK 127 4.2 FINITE0-RANK 130 4.3 THECONNECTIONSBETWEENTHEVARIOUSRANK CONDITIONSI 133 4.4 FINITESECTIONRANK 134 4.5 BOUNDEDSECTIONRANK 138 4.6 THECONNECTIONSBETWEENTHEVARIOUSRANK CONDITIONSII 139 4.7 FINITELYGENERATEDGROUPS 143 4.8 SYSTEMSOFSUBGROUPSSATISFYINGRANKCONDITIONS 146 4.9 SOMERESIDUALSYSTEMS 149 References for Chapter 4 153 Chapter 5(cid:4) Conjugacy Classes 159 5.1 AROUND “SCHUR’S THEOREM”, CENTRAL-BY-FINITE GROUPS ANDRELATEDTOPICS 160 5.2 BOUNDEDCONJUGACYCLASSES,FINITE-BY-ABELIANGROUPS ANDRELATEDCLASSES 172 5.3 GROUPSWITHFINITECLASSESOFCONJUGATEELEMENTS 177 5.4 SOMECONCLUDINGREMARKS 192 References for Chapter 5 193 Chapter 6(cid:4) Generalized Normal Subgroups and their Opposites 203 6.1 GROUPSWHOSESUBGROUPSARENORMAL,PERMUTABLEOR SUBNORMAL 204 6.2 GROUPSHAVINGALARGEFAMILYOFNORMALSUBGROUPS 211 Contents (cid:4) ix 6.3 GROUPSHAVINGALARGEFAMILYOFSUBNORMAL SUBGROUPS 218 6.4 PAIRSOFOPPOSITESUBGROUPS 225 6.5 TRANSITIVELYNORMALSUBGROUPS 234 6.6 THENORMOFAGROUP,THEWIELANDTSUBGROUPAND RELATEDTOPICS 243 6.7 THENORMOFAGROUPANDTHEQUASICENTRALIZER CONDITION 249 References for Chapter 6 254 Chapter 7(cid:4) Locally Finite Groups 269 7.1 PRELIMINARIES 269 7.2 LARGELOCALLYFINITEGROUPS 272 7.3 SIMPLELOCALLYFINITEGROUPS 275 7.4 EXISTENTIALLYCLOSEDGROUPS 282 7.5 CENTRALIZERSINLOCALLYFINITEGROUPS 284 7.6 SYLOWTHEORYINLOCALLYFINITEGROUPS 288 7.7 CONJUGACYOFSYLOWSUBGROUPS 290 7.8 UNCONVENTIONALSYLOWTHEORIES 294 7.9 SATURATEDFORMATIONSANDFITTINGCLASSES 297 7.10 BARELYTRANSITIVEGROUPS 301 References for Chapter 7 303 Bibliography 315 Author Index 377 Symbol Index 381 Subject Index 385