9 citations · 16 across the 23 of their papers we have counts for
4 papers · 1 filter
Universal spectra of the disjoint union of regular graphs
Willem H. Haemers, Mohammad Reza Oboudi
A universal adjacency matrix of a graph with adjacency matrix is any matrix of the form with , where is the identity matrix, is the…
Spectral symmetry in conference matrices
Willem H. Haemers, Leila Parsaei Majd
A conference matrix of order is an matrix with diagonal entries and off-diagonal entries satisfying . If is symmetric, then …
On sign-symmetric signed graphs
Ebrahim Ghorbani, Willem H. Haemers, Hamid Reza Maimani +1
A signed graph is said to be sign-symmetric if it is switching isomorphic to its negation. Bipartite signed graphs are trivially sign-symmetric. We give new constructions of non-bi…
On NP-hard graph properties characterized by the spectrum
Omid Etesami, Willem H. Haemers
Properties of graphs that can be characterized by the spectrum of the adjacency matrix of the graph have been studied systematically recently. Motivated by the complexity of these…