出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/01/17 00:04 UTC 版)
In graph theory, a branch of mathematics, a crown graph on 2n vertices is an undirected graph with two sets of vertices ui and vi and with an edge from ui to vj whenever i ≠ j. The crown graph can be viewed as a complete bipartite graph from which the edges of a perfect matching have been removed, as the bipartite double cover of a complete graph, or as a bipartite Kneser graph Hn,1 representing the 1-item and (n − 1)-item subsets of an n-item set, with an edge between two subsets whenever one is contained in the other.