Symmetries

From the reviews: MATHEMATICAL REVIEWS "This book is an inviting exposition to basic group theory and geometry and the close relationship between both in the context of studying symmetries. The approach taken by the author as well as the topics included and the many exercises present make it an excellent book for undergraduates, and not only in mathematics...The contents, the style, the accessibility, the examples and exercises and to do's make this book a highly recommended introductory work for anybody having an interest in understanding geometrical ideas through a group theory language." "The study of symmetry by means of group theory is an especially suited topic for undergraduates. The author treats mainly plane geometry ... . The group theoretical material is developed from scratch and goes finally beyond the usual topics ... . Also the throughout consequent use of group theoretic arguments is not commonplace. All in all a very recommendable book for undergraduates." (G. Kowol, Monatshefte fur Mathematik, Vol. 139 (1), 2003) "D. L. Johnson's Symmetries is based on lecture courses for mathematics students at Nottingham University and at the University of the West Indies, and is written in a friendly style. Some sections will also be of interest to physicists and crystallographers. Prerequisite knowledge is limited to a good understanding of sets and functions ... . Each chapter has a number of exercises." (Nigel Steele, Times Higher Education Supplement, November, 2002) "This book is an inviting exposition to basic group theory and geometry and the close relationship between both in the context of studying symmetries. The approach taken by the author as well as the topics included and the many exercises present make it an excellent book for undergraduates, and not only in mathematics. ... The contents, the style, the accessibility, the examples and the exercises and to do's make this book a highly recommended introductory work ... ." (Paul Igodt, Mathematical Reviews, Issue 2001 m) "The book studies geometry via group theory to express geometric ideas. ... It offers complete derivation and classification of the 17 plane crystallographic groups and guides suggestion to further reading. Each chapter contains a number of exercises, most with solutions. This book is suitable for all undergraduate geometry courses and for architects, physicists and crystallographers needing an understanding of 3-dimensional geometry, symmetry and trigonometry." (Jozef Fiamcik, Zentralblatt MATH, Vol. 980, 2002) "The main object of study for this book is geometry, with group theory providing an appropriate language in which to express geometrical ideas. Key features include: An overview of the preliminaries from group theory and geometry; ... a clear and complete derivation and classification of the 17 plane crystallographic groups; tessellations of various spaces (they are constructed, described and classified), a brief introduction to hyperbolic geometry. Each chapter contains a number of exercises, most with solutions, and suggestions for background, alternative and further reading." (L'Enseignement Mathematique, Vol. 47 (3-4), 2001)

• 1 Metric Spaces and their Groups.- 1.1 Metric Spaces.- 1.2 Isometries.- 1.3 Isometries of the Real Line.- 1.4 Matters Arising.- 1.5 Symmetry Groups.- 2 Isometries of the Plane.- 2.1 Congruent Triangles.- 2.2 Isometries of Different Types.- 2.3 The Normal Form Theorem.- 2.4 Conjugation of Isometries.- 3 Some Basic Group Theory.- 3.1 Groups.- 3.2 Subgroups.- 3.3 Factor Groups.- 3.4 Semidirect Products.- 4 Products of Reflections.- 4.1 The Product of Two Reflections.- 4.2 Three Reflections.- 4.3 Four or More.- 5 Generators and Relations.- 5.1 Examples.- 5.2 Semidirect Products Again.- 5.3 Change of Presentation.- 5.4 Triangle Groups.- 5.5 Abelian Groups.- 6 Discrete Subgroups of the Euclidean Group.- 6.1 Leonardo’s Theorem.- 6.2 A Trichotomy.- 6.3 Friezes and Their Groups.- 6.4 The Classification.- 7 Plane Crystallographic Groups: OP Case.- 7.1 The Crystallographic Restriction.- 7.2 The Parameter n.- 7.3 The Choice of b.- 7.4 Conclusion.- 8 Plane Crystallographic Groups: OR Case.- 8.1 A Useful Dichotomy.- 8.2 The Case n = 1.- 8.3 The Case n = 2.- 8.4 The Case n = 4.- 8.5 The Case n = 3.- 8.6 The Case n = 6.- 9 Tessellations of the Plane.- 9.1 Regular Tessellations.- 9.2 Descendants of (4, 4).- 9.3 Bricks.- 9.4 Split Bricks.- 9.5 Descendants of (3, 6).- 10 Tessellations of the Sphere.- 10.1 Spherical Geometry.- 10.2 The Spherical Excess.- 10.3 Tessellations of the Sphere.- 10.4 The Platonic Solids.- 10.5 Symmetry Groups.- 11 Triangle Groups.- 11.1 The Euclidean Case.- 11.2 The Elliptic Case.- 11.3 The Hyperbolic Case.- 11.4 Coxeter Groups.- 12 Regular Polytopes.- 12.1 The Standard Examples.- 12.2 The Exceptional Types in Dimension Four.- 12.3 Three Concepts and a Theorem.- 12.4 Schläfli’s Theorem.- Solutions.- Guide to the Literature.- Index of Notation.