arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1803.08641math.COcs.DM
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差图与偏序集的局部维数

On difference graphs and the local dimension of posets

Jinha Kim, Ryan R. Martin, Tomáš Masařík, Warren Shull, Heather C. Smith, Andrew Uzzell, Zhiyu Wang

摘要:

由Dushnik和Miller(1941)引入的偏序集(偏序集)的维数在文献中得到了广泛的研究。最近,Ueckerdt(2016)提出了一种称为局部维数的变体,它利用了部分线性扩展。虽然局部维度在上面由维度限定,但是它们可以任意远离,因为标准示例的维度是$n$,而其局部维度仅是$3$。Hiraguchi(1955)证明了$n$阶偏序集的最大维数是$n/2$。然而,我们发现了一个非常不同的结果,证明了$Θ(n/\log n)$的一个界。这是从使用差图的覆盖图的连接得出的,差图是二部图,其顶点在单个类中具有嵌套的邻域。我们还证明了$n$维布尔格的局部维数是$Ω(n/\log n)$,并在解决局部维数的可去对猜想方面取得了进展。

英文摘要:

The dimension of a partially-ordered set (poset), introduced by Dushnik and Miller (1941), has been studied extensively in the literature. Recently, Ueckerdt (2016) proposed a variation called local dimension which makes use of partial linear extensions. While local dimension is bounded above by dimension, they can be arbitrarily far apart as the dimension of the standard example is $n$ while its local dimension is only $3$. Hiraguchi (1955) proved that the maximum dimension of a poset of order $n$ is $n/2$. However, we find a very different result for local dimension, proving a bound of $Θ(n/\log n)$. This follows from connections with covering graphs using difference graphs which are bipartite graphs whose vertices in a single class have nested neighborhoods. We also prove that the local dimension of the $n$-dimensional Boolean lattice is $Ω(n/\log n)$ and make progress toward resolving a version of the removable pair conjecture for local dimension.

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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