论文标题

设置没有简单,Helly Hypergraphs和工会效率家庭的系统

Set systems without a simplex, Helly hypergraphs and union-efficient families

论文作者

Cambie, Stijn, Salia, Nika

论文摘要

我们提供了与集体相关的概念的等效公式,每个子家族都有空的交叉点都有一个有界的子收集与空的交叉点。在此,我们总结了有关此类家庭最大规模的相关问题的进展。 在这项工作中,我们通过应用Karamata的不平等,确定了一个以$ 2 $ 2 $的自我为中心的图表,解决了Tuza问题的边界案例。

We present equivalent formulations for concepts related to set families for which every subfamily with empty intersection has a bounded sub-collection with empty intersection. Hereby, we summarize the progress on the related questions about the maximum size of such families. In this work we solve a boundary case of a problem of Tuza for non-trivial $q$-Helly families, by applying Karamata's inequality and determining the minimum size of a $2$-self-centered graph for which the common neighborhood of every pair of vertices contains a clique of size $q-2$.

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