论文标题

在匹配覆盖的图中紧密切割的注释

A note on tight cuts in matching-covered graphs

论文作者

Zhao, Xiao, Chen, Sheng

论文摘要

Edmonds,Lovász和Pulleyblank表明,如果匹配的覆盖图具有非平凡的紧身切割,那么它也具有非平凡的ELP切割。 Carvalho等。给出了更强的猜想:如果匹配的覆盖图具有非平凡的紧身$ C $,那么它还具有非平凡的ELP切割,不会超过$ c $。 Chen等人给出了猜想的证明。此注释灵感来自Carvalho等人的论文。我们给出了简化的猜想证明,并证明了以下结果比猜想要强一些:如果非平凡的紧密切割$ c $的匹配图形$ g $不是ELP切割,则有一个序列$ g_1 = g_1 = g,g_2,g_2,\ ldots,\ ldots,g_r,g_r,g_r,r \ e \ geq2 $ for Matching of Groups $ -1,例如,c,例如,c,例如,y-ld,r f \ l f \ ld,r f \ l f。 $ g_i $具有elp-cut $ c_i $,$ g_ {i+1} $是$ c_i $ -g_i $的$ c_i $ - co $,$ c $是$ 2 $ - 分类削减$ g_r $。

Edmonds, Lovász, and Pulleyblank showed that if a matching covered graph has a nontrivial tight cut, then it also has a nontrivial ELP-cut. Carvalho et al. gave a stronger conjecture: if a matching covered graph has a nontrivial tight cut $C$, then it also has a nontrivial ELP-cut that does not cross $C$. Chen, et al gave a proof of the conjecture. This note is inspired by the paper of Carvalho et al. We give a simplified proof of the conjecture, and prove the following result which is slightly stronger than the conjecture: if a nontrivial tight cut $C$ of a matching covered graph $G$ is not an ELP-cut, then there is a sequence $G_1=G, G_2,\ldots,G_r, r\geq2$ of matching covered graphs, such that for $i=1, 2,\ldots, r-1$, $G_i$ has an ELP-cut $C_i$, and $G_{i+1}$ is a $C_i$-contraction of $G_i$, and $C$ is a $2$-separation cut of $G_r$.

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