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arXiv 2205.03389math.CO
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无冗余超平面覆盖

Irredundant hyperplane covers

János Nagy, Péter Pál Pach, István Tomon

摘要:

我们证明了如果$G$是一个阿贝尔群,并且$H_1x_1,\dots,H_{k}x_k$是$G$的一个带陪集的无冗余(最小)覆盖,则$$|G:\bigcap_{i=1}^{k}H_{i}|=2^{O(k)}.$$这个界是直到$O(\cdot)$符号中隐藏的常数为止的最佳可能界,并且它解决了Pyber(1996)和Szegedy(2007)的问题。进一步证明了如果$G$是某个大素数$p$的初等$p$ -群,并且$H_1,\dots,H_k$是一个具有多次重复的超平面序列,则上述界可以得到改进.因此,我们建立了一个实质性的加强最近解决的Alon-Jaeger-Tarsi猜想:存在$α>0$,使得对于每个可逆矩阵$M\in\mathbb{F}_p^{n\times n}$和任何一组至多$p^α$禁止坐标,可以找到一个矢量$x\in\mathbb{F}_p^{n}$,使得$x$和$Mx$都没有禁止坐标。

英文摘要:

We prove that if $G$ is an abelian group and $H_1x_1,\dots,H_{k}x_k$ is an irredundant (minimal) cover of $G$ with cosets, then $$|G:\bigcap_{i=1}^{k}H_{i}|=2^{O(k)}.$$ This bound is the best possible up to the constant hidden in the $O(\cdot)$ notation, and it resolves conjectures of Pyber (1996) and Szegedy (2007). We further show that if $G$ is an elementary $p$-group for some large prime $p$, and $H_1,\dots,H_k$ is a sequence of hyperplanes with many repetitions, then the bound above can be improved. As a consequence, we establish a substantial strengthening of the recently solved Alon-Jaeger-Tarsi conjecture: there exists $α>0$ such that for every invertible matrix $M\in\mathbb{F}_p^{n\times n}$ and any set of at most $p^α$ forbidden coordinates, one can find a vector $x\in\mathbb{F}_p^{n}$ such that neither $x$ nor $Mx$ have a forbidden coordinate.

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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