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arXiv 2512.07751math.CO
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精确的支撑度数界限用于哈密顿回路

Exact supported co-degree bounds for Hamilton cycles

University College London(伦敦大学学院)

Shoham Letzter, Arjun Ranganathan

AI总结:

本文研究了k-图中哈密顿回路的存在性,通过引入最小支撑度数条件,证明了在特定条件下k-图必然包含哈密顿回路,并改进了相关结果。

摘要:

对于任何k≥3和ℓ∈[k−1],且(k,ℓ)≠(3,1),我们证明了任何足够大的k-图G必须包含一个哈密顿ℓ-回路,前提是它没有孤立顶点,并且每个包含在边中的k−1个顶点至少包含(1−1/⌊k/k−ℓ⌋(k−ℓ))n−(k−3)条边。我们还证明这个界限对于无限多个k和ℓ的值是紧的,并且对于所有其他情况,这个界限与实际值相差至多1,因此本质上是最优的。这一结果改进了Mycroft和Zárate-Guerén关于此问题的渐近版本的结果,并且在ℓ=k−1的情况下完全解决了Illingworth、Lang、Müyesser、Parczyk和Sgueglia的猜想。这些结果支持了k-图中最小支撑度数条件的实用性,这是一种最近引入的、适用于具有非平凡强独立集的k-图的标准度数概念的变体。我们的证明技术涉及Lang引入的一种新颖的爆破铺砌框架,避免了传统方法中使用正则性和爆破引理的途径。

英文摘要:

For any $k\ge 3$ and $\ell \in [k-1]$ such that $(k,\ell) \ne (3,1)$, we show that any sufficiently large $k$-graph $G$ must contain a Hamilton $\ell$-cycle provided that it has no isolated vertices and every set of $k-1$ vertices contained in an edge is contained in at least $\left(1 - \frac{1}{\lfloor{\frac{k}{k-\ell}\rfloor}(k-\ell)}\right)n - (k - 3)$ edges. We also show that this bound is tight for infinitely many values of $k$ and $\ell$ and is off by at most $1$ for all others, and is hence essentially optimal. This improves an asymptotic version of this result due to Mycroft and Zárate-Guerén, and the case $\ell = k-1$ completely resolves a conjecture of Illingworth, Lang, Müyesser, Parczyk and Sgueglia. These results support the utility of $\textit{minimum}$ $\textit{supported}$ $\textit{co-degree}$ conditions in a $k$-graph, a recently introduced variant of the standard notion of minimum co-degree applicable to $k$-graphs with non-trivial strong independent sets. Our proof techniques involve a novel blow-up tiling framework introduced by Lang, avoiding traditional approaches using the regularity and blow-up lemmas.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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