论文标题
最高分配中的积分差距的改善:或北极的拓扑
Improved Integrality Gap in Max-Min Allocation: or Topology at the North Pole
论文作者
论文摘要
在最高分配问题中,一组$ p $的播放器将被分配为不可分割的资源的一组$ r $的差异子集,以便最大程度地提高所有播放器中的最低效用。我们研究了受限制的变体,也称为圣诞老人问题,每个资源都有内在的正值,每个参与者都垂涎的是资源的子集。 Bezáková和Dani表明,这个问题在不到$ 2 $的因素之内是NP-HARD的大约,因此,大量工作集中在近似解决方案上。获得近似算法的主要方法是通过Bansal和Sviridenko的配置LP(CLP)。因此,在界定此CLP的整体差距方面引起了极大的兴趣。现有的算法和完整性差距估计都以一种或另一种方式基于Haxell的组合增强树的参数,以在某些HyperGraphs中找到完美的匹配。本文我们的主要创新是介绍拓扑方法来限制最大分配问题,以取代组合论证。这种方法在CLP的完整性差距方面得到了重大改善。特别是,我们将$ 3.808 $的先前最著名的限制提高到$ 3.534 $。我们还研究了$(1,\ varepsilon)$限制版本,其中资源只能占两个值,并在大多数情况下改善整体差距。
In the max-min allocation problem a set $P$ of players are to be allocated disjoint subsets of a set $R$ of indivisible resources, such that the minimum utility among all players is maximized. We study the restricted variant, also known as the Santa Claus problem, where each resource has an intrinsic positive value, and each player covets a subset of the resources. Bezáková and Dani showed that this problem is NP-hard to approximate within a factor less than $2$, consequently a great deal of work has focused on approximate solutions. The principal approach for obtaining approximation algorithms has been via the Configuration LP (CLP) of Bansal and Sviridenko. Accordingly, there has been much interest in bounding the integrality gap of this CLP. The existing algorithms and integrality gap estimations are all based one way or another on the combinatorial augmenting tree argument of Haxell for finding perfect matchings in certain hypergraphs. Our main innovation in this paper is to introduce the use of topological methods for the restricted max-min allocation problem, to replace the combinatorial argument. This approach yields substantial improvements in the integrality gap of the CLP. In particular we improve the previously best known bound of $3.808$ to $3.534$. We also study the $(1,\varepsilon)$-restricted version, in which resources can take only two values, and improve the integrality gap in most cases.