On the rank of a cograph

Gerard J. Chang, Liang Hao Huang, Hong Gwa Yeh

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


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.

Original languageEnglish
Pages (from-to)601-605
Number of pages5
JournalLinear Algebra and Its Applications
Issue number2-3
StatePublished - 15 Jul 2008


  • Cograph
  • Complement reducible graph
  • Decomposable graph
  • Join
  • Rank
  • Twins
  • Union


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