论文标题

图形的连接性和可调性,没有$ k_t $ binor

Connectivity and choosability of graphs with no $K_t$ minor

论文作者

Norin, Sergey, Postle, Luke

论文摘要

1943年,哈德威格(Hadwiger)猜想,每张无$ k_t $ binor的图形都是$(t-1)$ - 每$ t \ ge 1 $可着色。尽管Hadwiger的猜想不适合列表颜色,但线性削弱的猜想是正确的。在1980年代,Kostochka和Thomason独立证明,每个无$ k_t $ binor的图形都有平均度$ o(t \ sqrt {\ log t})$,因此是$ o(t \ sqrt {\ log t} {\ log t})$ - list-list-colorable。最近,作者和歌曲证明,没有$ k_t $ binor的每个图为$ o(t(\ log t)^β)$ - 每$β> \ frac 1 4 $可着色。在这里,我们以此为基础,表明每个无$ k_t $ binor的图形为$ o(t(\ log t)^β)$ - 对于每$β> \ frac 1 4 $都可以列表上色。 我们的主要新工具是高度连接的$ k_t $ -minor-minor-frebragrs中的顶点的上限:我们证明,对于每$β> \ frac 1 4 $,每个$ω(t(\ log t)^β)$连接的图形,没有$ k_t $ o o(t(\ log log t(\ log t)^$ o(\ log t)^$ vertice。

In 1943, Hadwiger conjectured that every graph with no $K_t$ minor is $(t-1)$-colorable for every $t\ge 1$. While Hadwiger's conjecture does not hold for list-coloring, the linear weakening is conjectured to be true. In the 1980s, Kostochka and Thomason independently proved that every graph with no $K_t$ minor has average degree $O(t\sqrt{\log t})$ and thus is $O(t\sqrt{\log t})$-list-colorable. Recently, the authors and Song proved that every graph with no $K_t$ minor is $O(t(\log t)^β)$-colorable for every $β> \frac 1 4$. Here, we build on that result to show that every graph with no $K_t$ minor is $O(t(\log t)^β)$-list-colorable for every $β> \frac 1 4$. Our main new tool is an upper bound on the number of vertices in highly connected $K_t$-minor-free graphs: We prove that for every $β> \frac 1 4$, every $Ω(t(\log t)^β)$-connected graph with no $K_t$ minor has $O(t (\log t)^{7/4})$ vertices.

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