关于高围长高色数子图的 Erdős-Hajnal 问题的解
On the solution to the Erdős-Hajnal problem on high-girth high-chromatic subgraphs
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中文总结 AI 辅助
本文解释并优化了 Erdős-Hajnal 问题的高围长高色数子图的否定构造,将 Kohlmeyer 和 Kruer 的色数上界从 6 改进到 3。
中文摘要 AI 辅助
Erdős 和 Hajnal 在 1960 年代提出的一个著名问题询问:是否每个具有巨大色数的图都包含一个具有大围长和大色数的子图。最近,Kohlmeyer 和 Kruer 对该问题给出了一个强有力的否定解:构造了无三角形图,其色数任意大,但所有不含四圈的子图的色数至多为 $6$。本文旨在解释该构造方法,将其与相关文献联系起来,并将界 `$6$' 优化为 `$3$'。
英文摘要
A well-known problem of Erdős and Hajnal from the 1960s asks whether every graph with huge chromatic number contains a subgraph with large girth and large chromatic number. Very recently, Kohlmeyer and Kruer provided a strong negative solution to this problem: a construction of triangle-free graphs with arbitrarily large chromatic number whose subgraphs with no four-cycle have chromatic number at most $6$. The purpose of this exposition is to explain the construction method, relate it to relevant literature, and optimise the bound '$6$' to '$3$'.
发表机构
- University of Oxford(牛津大学)
- Jagiellonian University(雅盖隆大学)
机构由 AI 辅助整理,请以论文原文为准。