Godsil-McKay switching and isomorphism,

Aida Abiad, A.E. Brouwer, W. H. Haemers

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)


Godsil-McKay switching is an operation on graphs that doesn't change the spectrum of the adjacency matrix. Usually (but not always) the obtained graph is non-isomorphic with the original graph. We present a straightforward sucient condition for being isomorphic after switching, and give examples which show that this condition is not necessary. For some graph products we obtain sucient conditions for being non-isomorphic after switching. As an example we nd that the tensor product of the grid L(';m) (' > m 2) and a graph with at least one vertex of degree two is not determined by its adjacency spectrum.
Original languageEnglish
Pages (from-to)4-11
JournalElectronic Journal of Linear Algebra
Publication statusPublished - 2015


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