A ranking of a graph G is a mapping, p, from the vertices of G to the natural numbers such that for every path between any two vertices u and u, uf II, with p(u) = p(u), there exists at least one vertex w on that path with p(w) > p(u) = p(u). The value p(u) of a vertex u is the rank of vertex II. A
On the rank of a cograph
β Scribed by Gerard J. Chang; Liang-Hao Huang; Hong-Gwa Yeh
- Book ID
- 104037436
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 89 KB
- Volume
- 429
- Category
- Article
- ISSN
- 0024-3795
No coin nor oath required. For personal study only.
β¦ Synopsis
The rank of a graph is defined to be the rank of its adjacency matrix. Royle [G.F. Royle, The rank of a cograph, Electron. J. Combin. 10 (2003) #N11] proved a somewhat surprising result that the rank of a cograph is equal to the number of distinct non-zero rows of its adjacency matrix. In this paper we answer a question posed by Royle (2003) by giving an elementary short proof for a more general setting of this rank property of cographs.
π SIMILAR VOLUMES
A graph is called a cograph contraction if it is obtained from a cograph (a graph with no induced path on four vertices) by contracting some pairwise disjoint independent sets and then making the ''contracted'' vertices pairwise adjacent. Cograph contractions are perfect and generalize cographs and