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$3$-图和$3$部$3$-图中完美匹配的精确局部谱阈值

Exact local spectral thresholds for perfect matchings in $3$-graphs and $3$-partite $3$-graphs

Pei Liu, Suil O

arXiv 2609.26832首次发表:更新:

发表机构

Sungkyunkwan University; The State University of New York, Korea(成均馆大学; 纽约州立大学韩国分校)

机构由 AI 辅助整理,请以论文原文为准。

AI 中文总结

本文证明了大阶数下$3$-图和$q$-平衡$3$部$3$-图中基于局部谱半径的完美匹配猜想,通过分数匹配稳定性定理识别空间障碍。

AI 中文摘要

对于一个$3$-均匀超图$H$,设$\sigma(H)$为$H$的顶点上链接谱半径的最小值。Lin、Lu、Yuan和Zhao猜想,若$\sigma(H)>\frac{2n}{3}-2$,则在一个阶数$n$能被3整除的$3$-图中存在完美匹配;Lu和Yuan猜想,若$\sigma(H)>\tau(q)$,则在一个$q$-平衡的$3$部$3$-图中存在完美匹配,其中对于奇数$q$,$\tau(q)=\sqrt{q(q-1)/2}$,对于偶数$q$,$\tau(q)$由一个四次方程给出。在本文中,我们证明了大阶数下这两个完美匹配猜想。每个证明都通过一个关于分数匹配的稳定性定理:我们得到一个具有零坐标的权重不足的分数顶点覆盖,该顶点的链接承载诱导覆盖,并且该链接的谱半径由一个不等式界定,其极值情形识别出相应的空间障碍。

英文摘要

For a $3$-uniform hypergraph $H$, let $σ(H)$ be the minimum over the vertices of $H$ of the spectral radius of the link. Lin, Lu, Yuan and Zhao conjectured that $σ(H)>\tfrac{2n}3-2$ forces a perfect matching in a $3$-graph of order $n$ divisible by three, and Lu and Yuan conjectured that $σ(H)>τ(q)$ forces one in a $q$-balanced $3$-partite $3$-graph, where $τ(q)=\sqrt{q(q-1)/2}$ for odd $q$ and $τ(q)$ is given by a quartic for even $q$. In this paper, we prove both perfect matching conjectures for large order. Each proof passes through a stability theorem for fractional matchings: a fractional vertex cover of deficient weight with a zero coordinate is obtained, the link of that vertex carries the induced cover, and the spectral radius of such a link is bounded by an inequality whose extremal cases identify the corresponding space barriers.

Comments39 pages

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