论文标题

排除的未成年人几乎是脆弱的II:基本要素

Excluded minors are almost fragile II: essential elements

论文作者

Brettell, Nick, Oxley, James, Semple, Charles, Whittle, Geoff

论文摘要

令$ m $作为$ \ mathbb {p} $的类别排除在某些部分字段$ \ mathbb {p} $中的代表矩阵,让$ n $是$ 3 $ 3 $连接的$ \ mathbb {p mathbb {p} $ - $ m $ m $ $ m $ $ m $ $ m \ backslash a,b $是$ 3 $与$ n $ -minor连接的。还假设$ | e(m)| \ geq | e(n)|+11 $和$ m \ backslash a,b $不是$ n $ fragile。在本文的前传中,我们证明了$ m \ backslash a,b $最多距离$ n $ fragile Minor的五个要素。如果$ m'/e $ $ $ $ $ $ $ n $ n $ n $ n $ n nes元素$ e $是$ n $ $ n $ n $ n $ n $ n $ n $ n $ n $'\ backslash e $ $ n $ n $ -minor。在本文中,我们证明,在温和的假设下,$ m \ backslash a,b $与至少$ r(m)-2 $元素($ n $ exential-Essential-Extient)的未成年人距离是一个要素。

Let $M$ be an excluded minor for the class of $\mathbb{P}$-representable matroids for some partial field $\mathbb{P}$, let $N$ be a $3$-connected strong $\mathbb{P}$-stabilizer that is non-binary, and suppose $M$ has a pair of elements $\{a,b\}$ such that $M\backslash a,b$ is $3$-connected with an $N$-minor. Suppose also that $|E(M)| \geq |E(N)|+11$ and $M \backslash a,b$ is not $N$-fragile. In the prequel to this paper, we proved that $M \backslash a,b$ is at most five elements away from an $N$-fragile minor. An element $e$ in a matroid $M'$ is $N$-essential if neither $M'/e$ nor $M' \backslash e$ has an $N$-minor. In this paper, we prove that, under mild assumptions, $M \backslash a,b$ is one element away from a minor having at least $r(M)-2$ elements that are $N$-essential.

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