Journal of Combinatorial Theory Series A ( IF 0.9 ) Pub Date : 2022-03-17 , DOI: 10.1016/j.jcta.2022.105618 Andreas F. Holmsen 1 , Seunghun Lee 2
Given a graph G on the vertex set V, the non-matching complex of G, denoted by , is the family of subgraphs whose matching number is strictly less than k. As an attempt to extend the result by Linusson, Shareshian and Welker on the homotopy types of and to arbitrary graphs G, we show that (i) is -Leray, and (ii) if G is bipartite, then is -Leray. This result is obtained by analyzing the homology of the links of non-empty faces of the complex , which vanishes in all dimensions , and all dimensions when G is bipartite. As a corollary, we have the following rainbow matching theorem which generalizes a result by Aharoni, Berger, Chudnovsky, Howard and Seymour: Let be non-empty edge subsets of a graph and suppose that for every . Then has a rainbow matching of size k. Furthermore, the number of edge sets can be reduced to when E is the edge set of a bipartite graph.
中文翻译:
有界匹配数的图复数的 Leray 数
给定顶点集V上的图G , G的非匹配复数,表示为, 是子图族谁的匹配号码严格小于k。作为尝试扩展 Linusson、Shareshian 和 Welker 关于同伦类型的结果和对于任意图G,我们证明 (i)是-Leray,并且 (ii) 如果G是二分的,那么是-勒雷。这个结果是通过分析复合体的非空面链接的同源性得到的,在所有维度上消失, 和所有维度当G是二分的。作为推论,我们有以下彩虹匹配定理,它概括了 Aharoni、Berger、Chudnovsky、Howard 和 Seymour 的结果:是图的非空边子集并假设对于每个. 然后有大小为k的彩虹匹配。此外,边集的数量可以简化为当E是二部图的边集时。