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Nearly Perfect Matchings in Uniform Hypergraphs
SIAM Journal on Discrete Mathematics ( IF 0.8 ) Pub Date : 2021-05-17 , DOI: 10.1137/19m1300662
Hongliang Lu , Xingxing Yu , Xiaofan Yuan

SIAM Journal on Discrete Mathematics, Volume 35, Issue 2, Page 1022-1049, January 2021.
We prove that, for any integers $k,l$ with $k\ge 3$ and $k/2<l\leq k-1$, there exists a positive real $\mu$ such that, for all sufficiently large integers $m,n$ satisfying $ \frac{n}{k}-\mu n\le m\le \frac{n}{k} -1- (1-\frac{l}{k})\left\lceil\frac{k-l}{2l-k}\right\rceil, $ if $H$ is a $k$-uniform hypergraph on $n$ vertices and $\delta_{l}(H)>{n-l\choose k-l}-{(n-l)-m\choose k-l}$, then $H$ has a matching of size $m+1$. This improves upon an earlier result of Hàn, Person, and Schacht for the range $k/2<l\leq k-1$. In many cases, our result gives a tight bound on $\delta_l(H)$ for near perfect matchings (e.g., when $l\ge 2k/3$, $n\equiv r \pmod k$, $0\le r<k$, and $r+l\ge k$, we can take $m=\lceil n/k\rceil -2$). When $k=3$, using an absorbing lemma of Hàn, Person, and Schacht, our proof also implies a result of Kühn, Osthus, and Treglown (and, independently, of Khan) on perfect matchings in 3-uniform hypergraphs.


中文翻译:

均匀超图中的近乎完美匹配

SIAM 离散数学杂志,第 35 卷,第 2 期,第 1022-1049 页,2021 年 1 月。
我们证明,对于任何具有 $k\ge 3$ 和 $k/2<l\leq k-1$ 的整数 $k,l$,存在一个正实数 $\mu$,使得对于所有足够大的整数$m,n$ 满足 $ \frac{n}{k}-\mu n\le m\le \frac{n}{k} -1- (1-\frac{l}{k})\left\ lceil\frac{kl}{2l-k}\right\rceil, $ 如果 $H$ 是 $n$ 个顶点上的 $k$-均匀超图并且 $\delta_{l}(H)>{nl\choose kl }-{(nl)-m\choose kl}$,则 $H$ 有大小为 $m+1$ 的匹配。这改进了 Hàn、Person 和 Schacht 在 $k/2<l\leq k-1$ 范围内的早期结果。在许多情况下,对于近乎完美的匹配(例如,当 $l\ge 2k/3$, $n\equiv r \pmod k$, $0\le r< k$,和 $r+l\ge k$,我们可以取 $m=\lceil n/k\rceil -2$)。当 $k=3$ 时,使用 Hàn、Person 和 Schacht 的引理,我们的证明还暗示了 Kühn、Osthus、
更新日期:2021-05-17
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