arXiv math/05062402005-06-13math.MGmath.DG

Three-dimensional antipodal and norm-equilateral sets

Achill Schuermann, Konrad Swanepoel

备注：: 20 pages, 15 figures
发表信息：: Pacific Journal of Mathematics 228 (2006), 349--370.

英文摘要：

We characterize the three-dimensional spaces admitting at least six or at least seven equidistant points. In particular, we show the existence of $C^\infty$ norms on $\R^3$ admitting six equidistant points, which refutes a conjecture of Lawlor and Morgan (1994, Pacific J. Math \textbf{166}, 55--83), and gives the existence of energy-minimizing cones with six regions for certain uniformly convex norms on $\R^3$. On the other hand, no differentiable norm on $\R^3$ admits seven equidistant points. A crucial ingredient in the proof is a classification of all three-dimensional antipodal sets. We also apply the results to the touching numbers of several three-dimensional convex bodies.

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