论文标题

联盟封锁的家庭的小型

Small Sets in Union-Closed Families

论文作者

Ellis, David, Ivan, Maria-Romina, Leader, Imre

论文摘要

我们在本说明中的目的是表明,对于任何$ε> 0 $,都存在一个联合封闭的家庭$ \ Mathcal f $,其中(唯一)最小的set $ s $,因此,$ s $的元素不属于$ \ \ \ \ \ \ \ \ m nathcal f $的$ s $的分数$ε$。更确切地说,我们举了一个示例,它的示例是一个最小的尺寸$ k $的联合锁定家庭,因此该集合中的任何元素都不属于$ \ \ \ mathcal f $ in $ \ mathcal f $的$(1+o(1))\ frac {\ frac {\ log_2 k} {2k} $。我们还提供了包含“小”集合的联盟锁定家庭的明确例子,我们无法验证工会关闭的猜想。

Our aim in this note is to show that, for any $ε>0$, there exists a union-closed family $\mathcal F$ with (unique) smallest set $S$ such that no element of $S$ belongs to more than a fraction $ε$ of the sets in $\mathcal F$. More precisely, we give an example of a union-closed family with smallest set of size $k$ such that no element of this set belongs to more than a fraction $(1+o(1))\frac{\log_2 k}{2k}$ of the sets in $\mathcal F$. We also give explicit examples of union-closed families containing `small' sets for which we have been unable to verify the Union-Closed Conjecture.

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