给定一个简单图G和正整数k,具有完美匹配的图G的k-导出匹配划分是对顶点集V(G)的一个k-划分(V1,V2,…,Vk),其中对每一个i(1≤i≤k),由Vi导出的G的子图G[Vi]是1-正则的.k-导出匹配划分问题是指对给定的图G,判定G是否存在一个k-导出匹配划分.令M1,M2…,Mk为图G的k个导出匹配,如果V(M1)U(M2)U…UV(Mk)=V(G),则我们称{M1,M2….,Mk)是G的k-导出匹配覆盖.k-导出匹配覆盖问题是指对给定的图G,判定G是否存在k-导出匹配覆盖.本文给出了Yang,Yuan和Dong所提出问题的解,证明了直径为5的图的导出匹配2-划分问题和导出匹配2-覆盖问题都是NP-完全的.
Given a simple graph G and a positive integer k, a k-induced-matching partition of a graph G having a perfect matching is a k-partition (V1, V2,……, Vk) of V (G) such that for each i (1 ≤ i ≤ k), the subgraph G [Vi] of G induced by Vi is 1-regular. The k-induced-matching partition problem asks whether a given graph G has a k-inducedmatching partition or not. Let M1,M2,... Mk be k induced matching of G. We say {M1, M2,..., Mk} is a k-induced-matching cover of G if V(M1) U V(M2) U... U V(Mk) = V(G). The k-induced-matching cover problem asks whether a given graph G has a k- induced-matching cover or not. In this paper, 2-induced-matching partition problem and 2-induced-matching cover problem of graphs with diameter 5 are proved to be NP- complete, which gives a solution of Yang Yuan and Dong.