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Zusatztext "[An] excellent introduction to other, important aspects of the study of geometric and topological approaches to group theory. Davis's exposition gives a delightful treatment of infinite Coxeter groups that illustrates their continued utility to the field." ---John Meier, Bulletin of the AMS Informationen zum Autor Michael W. Davis is professor of mathematics at Ohio State University. Klappentext The Geometry and Topology of Coxeter Groups is a comprehensive and authoritative treatment of Coxeter groups from the viewpoint of geometric group theory. Groups generated by reflections are ubiquitous in mathematics, and there are classical examples of reflection groups in spherical, Euclidean, and hyperbolic geometry. Any Coxeter group can be realized as a group generated by reflection on a certain contractible cell complex, and this complex is the principal subject of this book. The book explains a theorem of Moussong that demonstrates that a polyhedral metric on this cell complex is nonpositively curved, meaning that Coxeter groups are "CAT(0) groups." The book describes the reflection group trick, one of the most potent sources of examples of aspherical manifolds. And the book discusses many important topics in geometric group theory and topology, including Hopf's theory of ends; contractible manifolds and homology spheres; the Poincaré Conjecture; and Gromov's theory of CAT(0) spaces and groups. Finally, the book examines connections between Coxeter groups and some of topology's most famous open problems concerning aspherical manifolds, such as the Euler Characteristic Conjecture and the Borel and Singer conjectures. Zusammenfassung Presents a comprehensive treatment of Coxeter groups from the viewpoint of geometric group theory. This book discusses many important topics in geometric group theory and topology, including Hopf's theory of ends; contractible manifolds and homology spheres; the Poincare Conjecture; and Gromov's theory of CAT(0) spaces and groups. Inhaltsverzeichnis Preface xiii Chapter 1: INTRODUCTION AND PREVIEW 1 1.1 Introduction 1 1.2 A Preview of the Right-Angled Case 9 Chapter 2: SOME BASIC NOTIONS IN GEOMETRIC GROUP THEORY 15 2.1 Cayley Graphs and Word Metrics 15 2.2 Cayley 2-Complexes 18 2.3 Background on Aspherical Spaces 21 Chapter 3: COXETER GROUPS 26 3.1 Dihedral Groups 26 3.2 Reflection Systems 30 3.3 Coxeter Systems 37 3.4 The Word Problem 40 3.5 Coxeter Diagrams 42 Chapter 4: MORE COMBINATORIAL THEORY OF COXETER GROUPS 44 4.1 Special Subgroups in Coxeter Groups 44 4.2 Reflections 46 4.3 The Shortest Element in a Special Coset 47 4.4 Another Characterization of Coxeter Groups 48 4.5 Convex Subsets of W 49 4.6 The Element of Longest Length 51 4.7 The Letters with Which a Reduced Expression Can End 53 4.8 A Lemma of Tits 55 4.9 Subgroups Generated by Reflections 57 4.10 Normalizers of Special Subgroups 59 Chapter 5: THE BASIC CONSTRUCTION 63 5.1 The Space U 63 5.2 The Case of a Pre-Coxeter System 66 5.3 Sectors in U 68 Chapter 6: GEOMETRIC REFLECTION GROUPS 72 6.1 Linear Reflections 73 6.2 Spaces of Constant Curvature 73 6.3 Polytopes with Nonobtuse Dihedral Angles 78 6.4 The Developing Map 81 6.5 Polygon Groups 85 6.6 Finite Linear Groups Generated by Reflections 87 6.7 Examples of Finite Reflection Groups 92 6.8 Geometric Simplices: The Gram Matrix and the Cosine Matrix 96 6.9 Simplicial Coxeter Groups: LannÂ'er's Theorem 102 6.10 Three-dimensional Hyperbolic Reflection Groups: Andreev's Theorem 103 6.11 Higher-dimensional Hyperbolic Reflection Groups: Vinberg's Theorem 110 6.12 The Canonical Representation 115 Chapter 7: THE COMPLEX ? 123 7.1 The Nerve of a Coxeter System 123 7.2 Geometric Realizations 126 7.3 A Cell Structure on ? 128 7.4 Examples 132 7.5 Fixed Posets and Fixed Subspaces 133 Chapter 8: THE ALGEBRAIC TOPOLOGY OF U AND OF ? 136 8.1 The Homology of U 137 8.2 Acyclicity Conditions 140 8.3 Coho...
