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arXiv 1404.7019math.MG
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等宽物体的典型曲率特性

Typical curvature behaviour of bodies of constant width

Imre Barany, rolf Schneider

摘要:

已知在Baire范畴意义下典型的$n$维凸体表现出简单但高度非直观的曲率行为:在几乎所有的边界点处,在测度意义下,所有曲率为零,但也存在一个稠密且不可数的边界点集合,在该集合处所有曲率为无穷大。本文的目的是找到一个对应的典型凸体,给定的恒定宽度的现象。这样的物体不可能有零曲率。一个主要结果是,对于一个典型的等宽$1$的$n$维凸体(不失一般性),在几乎所有的边界点上,在测度意义下,所有的曲率都等于$1$ . (In相反,注意,宽度为$1$的球具有半径$1/2$,因此其所有曲率都等于$2$。)由于常数宽度的性质是线性的闵可夫斯基加法,证明需要求助于线性曲率的概念,这是由切线曲率半径提供的。

英文摘要:

It is known that an $n$-dimensional convex body which is typical in the sense of Baire category, shows a simple, but highly non-intuitive curvature behaviour: at almost all of its boundary points, in the sense of measure, all curvatures are zero, but there is also a dense and uncountable set of boundary points at which all curvatures are infinite. The purpose of this paper is to find a counterpart to this phenomenon for typical convex bodies of given constant width. Such bodies cannot have zero curvatures. A main result says that for a typical $n$-dimensional convex body of constant width $1$ (without loss of generality), at almost all boundary points, in the sense of measure, all curvatures are equal to $1$. (In contrast, note that a ball of width $1$ has radius $1/2$, hence all its curvatures are equal to $2$.) Since the property of constant width is linear with respect to Minkowski addition, the proof requires recourse to a linear curvature notion, which is provided by the tangential radii of curvature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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