Journal of Combinatorial Theory Series A ( IF 0.9 ) Pub Date : 2022-01-06 , DOI: 10.1016/j.jcta.2021.105583 Lei Yu 1
Let be the graph with vertex set in which two vertices are joined if their Hamming distance is at most r. The edge-isoperimetric problem for is that: For every such that and , determine the minimum edge-boundary size of a subset of vertices of with a given size M. In this paper, we apply two different approaches to prove bounds for this problem. The first approach is a linear programming approach and the second is probabilistic. Our bound derived by the first approach generalizes the tight bound for derived by Kahn, Kalai, and Linial in 1989. Moreover, our bound is also tight for and . Our bounds derived by the second approach are expressed in terms of the noise stability, and they are shown to be asymptotically tight as when and for fixed , and is tight up to a factor 2 when and . In fact, the edge-isoperimetric problem is equivalent to a ball-noise stability problem which is a variant of the traditional (i.i.d.-) noise stability problem. Our results can be interpreted as bounds for the ball-noise stability problem.
中文翻译:
边缘等周不等式和球噪声稳定性:线性规划和概率方法
让 是具有顶点集的图 如果两个顶点的汉明距离最多为r ,则它们连接在一起。边等周长问题 就是:对于每个 这样 和 ,确定顶点子集的最小边边界大小 给定大小M。在本文中,我们应用了两种不同的方法来证明这个问题的界限。第一种方法是线性规划方法,第二种方法是概率。我们通过第一种方法得出的界概括了紧界 由 Kahn、Kalai 和 Linial 在 1989 年推导出来的。此外,我们的界限也很紧 和 . 我们通过第二种方法得出的界限用噪声稳定性表示,并且它们被证明是渐近紧的 什么时候 和 对于固定 ,并且紧到因子 2 时 和 . 事实上,边缘等周问题等价于球噪声稳定性问题,它是传统(iid-)噪声稳定性问题的变体。我们的结果可以解释为球噪声稳定性问题的界限。