发表机构
National University of Singapore; University of Science and Technology of China; Tsinghua University; Georgia Institute of Technology(新加坡国立大学; 中国科学技术大学; 清华大学; 佐治亚理工学院)
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Erdős关于不含广义4-环的极值超图边数的猜想,确定了所有极值配置,并解决了Mubayi的猜想。
AI 中文摘要
1977年,Erdős提出了确定最大边数$f_r(n)$的问题,其中$f_r(n)$是$n$个顶点的$r$均匀超图中所有不相交边对具有不同并集时的最大边数。Füredi后来猜想,对于每个固定的$r\ge 4$和所有足够大的$n$,$f_r(n)=\binom{n-1}{r-1}+\lfloor \frac{n-1}{r}\rfloor$。在本文中,我们证明了这一猜想并确定了所有极值配置。我们的证明结合了针对此类稠密超图的稳定性定理,以及对关联的二部$3$-图应用的精细删除论证。稳定性定理还解决了Mubayi的一个猜想。
英文摘要
In 1977, Erdős posed the problem of determining the maximum number $f_r(n)$ of edges in an $n$-vertex $r$-uniform hypergraph in which all disjoint pairs of edges have distinct unions. Füredi later conjectured that, for every fixed $r\ge 4$ and all sufficiently large $n$, $f_r(n)=\binom{n-1}{r-1}+\lfloor \frac{n-1}{r}\rfloor$. In this paper, we prove this conjecture and determine all extremal configurations. Our proof combines a stability theorem for such dense hypergraphs with a delicate deletion argument applied to an associated bipartite $3$-graph. The stability theorem also resolves a conjecture of Mubayi.