9 citations · 16 across the 23 of their papers we have counts for
4 papers · 1 filter
Switched symplectic graphs and their 2-ranks
Aida Abiad, Willem H. Haemers
We apply Godsil-McKay switching to the symplectic graphs over with at least 63 vertices and prove that the 2-rank of (the adjacency matrix of) the graph increases af…
Cospectral regular graphs with and without a perfect matching
Zoltan L. Blazsik, Jay Cummings, Willem H. Haemers
For each we construct a pair of cospectral -regular graphs, where one has a perfect matching and the other one not. This solves a research problem posed by the third…
Notes on simplicial rook graphs
Andries E. Brouwer, Sebastian M. Cioabă, Willem H. Haemers +1
The simplicial rook graph is the graph of which the vertices are the sequences of nonnegative integers of length summing to , where two such sequences are ad…
Godsil-McKay switching and isomorphism
Aida Abiad, Andries E. Brouwer, Willem H. Haemers
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 or…