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Gruber P. Convex and Discrete Geometry

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<strong>Convex</strong> Polytopes<br />

The early history of convex polytopes is lost. About 2000 BC convex polytopes<br />

appeared in a mathematical context in the Sumerian civilization, in Babylonia <strong>and</strong> in<br />

Egypt. Sources are the Moscow papyrus <strong>and</strong> the Rhind papyrus. Some of the regular<br />

polytopes were already known by then. A basic problem was to calculate the volumes<br />

of truncated pyramids. This was needed to determine the number of bricks for<br />

fortifications <strong>and</strong> buildings. Babylonians sometimes did the calculations correctly,<br />

sometimes not, while Egyptians used the right formula. For pertinent information the<br />

author is obliged to the assyriologist Hermann Hunger [531]. In the fifth century BC<br />

Democritos also discovered this formula <strong>and</strong> Eudoxos proved it, using the method<br />

of exhaustion. Theaitetos developed a theory of regular polytopes, later treated by<br />

Plato in the dialogue Timaios. Euclid, around 300 BC, considered metric properties<br />

of polytopes, the volume problem, including the exhaustion method, <strong>and</strong> the<br />

five regular polytopes, the Platonic solids. Zenodoros, who lived sometime between<br />

200 BC <strong>and</strong> 90 AD, studied the isoperimetric problem for polygons <strong>and</strong> polytopes<br />

<strong>and</strong> Pappos, about 300 AD, dealt with the semi-regular polytopes of Archimedes.<br />

In the renaissance the study of convex polytopes was in the h<strong>and</strong>s of artists such<br />

as Uccello, Pacioli, da Vinci, Dürer, <strong>and</strong> Jamnitzer. Then it went back to mathematics.<br />

Kepler investigated the regular <strong>and</strong> the semi-regular polytopes <strong>and</strong> planar<br />

tilings. Descartes considered convex polytopes from a metric point of view, almost<br />

arriving at Euler’s polytope formula, discovered by Euler only hundred years later.<br />

Contributions to polytope theory in the late eighteenth <strong>and</strong> the nineteenth century<br />

are due to Legendre, Cauchy, Steiner, Schläfli <strong>and</strong> others. At the turn of the nineteenth<br />

<strong>and</strong> in the twentieth century important results were given by Minkowski,<br />

Dehn, Sommerville, Steinitz, Coxeter <strong>and</strong> numerous contemporaries. At present,<br />

emphasis is on the combinatorial, algorithmic, <strong>and</strong> algebraic aspects. Modern relations<br />

to other areas date back to Newton (polynomials), Fourier (linear optimization),<br />

Dirichlet, Minkowski <strong>and</strong> Voronoĭ (quadratic forms) <strong>and</strong> Fedorov (crystallography).<br />

In recent decades polytope theory was strongly stimulated <strong>and</strong>, in part, re-oriented<br />

by linear optimization, computer science <strong>and</strong> algebraic geometry. Polytope theory,<br />

in turn, had a certain impact on these areas. For the history, see Federico [318] <strong>and</strong><br />

Malkevitch [681].

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