Given any set of points $S$ in the unit square that contains the origin, does a set of axis aligned rectangles, one for each point in $S$, exist, such that each of them has a point in $S$ as its lower-left corner, they are pairwise interior disjoint, and the total area that they cover is at least 1/2? This question is also known as Freedman's conjecture (conjecturing that such a set of rectangles does exist) and has been open since Allen Freedman posed it in 1969. In this paper, we improve the best known lower bound on the total area that can be covered from 0.09121 to 0.1039. Although this step is small, we introduce new insights that push the limits of this analysis. Our lower bound uses a greedy algorithm with a particular order of the points in $S$. Therefore, it also implies that this greedy algorithm achieves an approximation ratio of 0.1039. We complement the result with an upper bound of 3/4 on the approximation ratio for a natural class of greedy algorithms that includes the one that achieves the lower bound.
翻译:在包含源代码的单位方形中,如果有任何一组点($S美元),是否有一组轴对齐矩形,每个点每个点每个点以$S美元,就存在,因此每个点的左下角有一个点($S美元),它们是对齐的内部脱节,它们覆盖的总面积至少为1/2?这个问题也被称为Freedman的猜测(暗示有一套矩形存在),并且自Allen Freedman1969年提出以来就一直开放。在本文中,我们改进了可以覆盖的总区域已知最低的界限,即从0.09121美元到0.1039美元,尽管这一步骤很小,但我们提出了新的见解,推动了这一分析的极限。我们较低的界限使用贪婪的算法,其具体顺序是1/2美元。因此,它也意味着贪婪的算法达到了0.1039的近似率。我们用3/4的近似比来补充这一结果,该结果涉及天然贪婪算算法的直观率率,其中包括达到较低约束的算法。