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math.CO2024
Degree-Similar Graphs
Chris Godsil, Wanting Sun
The degree matrix of a graph is the diagonal matrix with diagonal entries equal to the degrees of the vertices of . If and are graphs with respective adjacency matri…
math.CO2024
Oriented or signed Cayley graphs with all eigenvalues integer multiples of
Chris Godsil, Xiaohong Zhang
Let be a finite abelian group. Bridges and Mena characterized the Cayley graphs of that have only integer eigenvalues. Here we consider the adjacency matrix of a…
math.CO2024
Quantum independence and chromatic numbers
Chris Godsil, Mariia Sobchuk
We construct a new graph on 120 vertices whose quantum and classical independence numbers are different. At the same time, we construct an infinite family of graphs whose quantum c…