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arXiv 1209.4652math.MGmath.CO
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关于带形格的Voronoi多面体的和

On the sum of the Voronoi polytope of a lattice with a zonotope

Mathieu Dutour Sikiric, Viatcheslav Grishukhin, Alexander Magazinov

摘要:

平行多面体$P$是一种多面体,它允许通过沿晶格平移$P$的副本来进行面到面的空间平铺。格子$L$的Voronoi单元$P_V(L)$是平行体的一个例子。平行体可以被唯一地分解为区域封闭平行体$P$和带形$Z(U)$的Minkowski和,其中$U$是用于生成带形的向量的集合。本文考虑了与此相关的问题:一般平行体与带形$P+Z(U)$的Minkowski和何时是平行体?我们给出了两个必要条件,并证明了向量$U$必须是自由的。给定一个自由向量集$U$,给出了几种判断$P + Z(U)$是否为平行体的方法.利用这一点,我们对一些高度对称的格的zonotopes进行分类。在根格$\mathsf{E}_6$的情况下,可以给出向量$U$的容许集合的更多几何描述。我们发现,一组容许向量,称为自由向量,是由众所周知的配置$27$线在一个立方。在详细研究$P_V(\mathsf{e}_6)$几何的基础上,给出了矢量$U$的构型的一个简单刻画,使得$P_V(\mathsf{E}_6) + Z(U)$是一个平行体.枚举产生$10$最大的家庭的向量,这是由他们的描述为正规拟阵。

英文摘要:

A parallelotope $P$ is a polytope that admits a facet-to-facet tiling of space by translation copies of $P$ along a lattice. The Voronoi cell $P_V(L)$ of a lattice $L$ is an example of a parallelotope. A parallelotope can be uniquely decomposed as the Minkowski sum of a zone closed parallelotope $P$ and a zonotope $Z(U)$, where $U$ is the set of vectors used to generate the zonotope. In this paper we consider the related question: When is the Minkowski sum of a general parallelotope and a zonotope $P+Z(U)$ a parallelotope? We give two necessary conditions and show that the vectors $U$ have to be free. Given a set $U$ of free vectors, we give several methods for checking if $P + Z(U)$ is a parallelotope. Using this we classify such zonotopes for some highly symmetric lattices. In the case of the root lattice $\mathsf{E}_6$, it is possible to give a more geometric description of the admissible sets of vectors $U$. We found that the set of admissible vectors, called free vectors, is described by the well-known configuration of $27$ lines in a cubic. Based on a detailed study of the geometry of $P_V(\mathsf{e}_6)$, we give a simple characterization of the configurations of vectors $U$ such that $P_V(\mathsf{E}_6) + Z(U)$ is a parallelotope. The enumeration yields $10$ maximal families of vectors, which are presented by their description as regular matroids.

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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