# Geometry and the Imagination

AMS Chelsea Pub., 1999 - Mathematics - 357 pages
This remarkable book endures as a true masterpiece of mathematical exposition. The book is overflowing with mathematical ideas, which are always explained clearly and elegantly, and above all, with penetrating insight. It is a joy to read, both for beginners and experienced mathematicians. Geometry and the Imagination is full of interesting facts, many of which you wish you had known before. The book begins with examples of the simplest curves and surfaces, including thread constructions of certain quadrics and other surfaces. The chapter on regular systems of points leads to the crystallographic groups and the regular polyhedra in $\mathbb{R}^3$. In this chapter, they also discuss plane lattices. By considering unit lattices, and throwing in a small amount of number theory when necessary, they effortlessly derive Leibniz's series: $\pi/4 = 1 - 1/3 + 1/5 - 1/7 + - \ldots$. In the section on lattices in three and more dimensions, the authors consider sphere-packing problems, including the famous Kepler problem. One of the most remarkable chapters is Projective Configurations''. In a short introductory section, Hilbert and Cohn-Vossen give perhaps the most concise and lucid description of why a general geometer would care about projective geometry and why such an ostensibly plain setup is truly rich in structure and ideas. The chapter on kinematics includes a nice discussion of linkages and the geometry of configurations of points and rods that are connected and, perhaps, constrained in some way. This topic in geometry has become increasingly important in recent times, especially in applications to robotics. This is another example of a simple situation that leads to a rich geometry. It would be hard to overestimate the continuing influence Hilbert-Cohn-Vossen's book has had on mathematicians of this century. It surely belongs in the "pantheon" of great mathematics books.

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#### Review: Geometry and the Imagination

User Review  - Diana - Goodreads

Yesterday, I learned what an oblate spheroid is. Also a prolate spheroid (which I hadn't heard of before.) If you rotate an ellipse on its major (longer) axis you get a prolate spheroid (which looks ... Read full review

### About the author (1999)

Born in Konigsberg, Germany, David Hilbert was professor of mathematics at Gottingen from 1895 to1930. Hilbert was among the earliest adherents of Cantor's new transfinite set theory. Despite the controversy that arose over the subject, Hilbert maintained that "no one shall drive us from this paradise (of the infinite)" (Hilbert, "Uber das Unendliche," Mathematische Annalen [1926]). It has been said that Hilbert was the last of the great universalist mathematicians and that he was knowledgeable in every area of mathematics, making important contributions to all of them (the same has been said of Poincare). Hilbert's publications include impressive works on algebra and number theory (by applying methods of analysis he was able to solve the famous "Waring's Problem"). Hilbert also made many contributions to analysis, especially the theory of functions and integral equations, as well as mathematical physics, logic, and the foundations of mathematics. His work of 1899, Grundlagen der Geometrie, brought Hilbert's name to international prominence, because it was based on an entirely new understanding of the nature of axioms. Hilbert adopted a formalist view and stressed the significance of determining the consistency and independence of the axioms in question. In 1900 he again captured the imagination of an international audience with his famous "23 unsolved problems" of mathematics, many of which became major areas of intensive research in this century. Some of the problems remain unresolved to this day. At the end of his career, Hilbert became engrossed in the problem of providing a logically satisfactory foundation for all of mathematics. As a result, he developed a comprehensive program to establish the consistency of axiomatized systems in terms of a metamathematical proof theory. In 1925, Hilbert became ill with pernicious anemia---then an incurable disease. However, because Minot had just discovered a treatment, Hilbert lived for another 18 years.