A note on the spectra and eigenspaces of the universal adjacency matrices of arbitrary lifts of graphs

C. Dalfó, M. A. Fiol, S. Pavlíková +1

The universal adjacency matrix $U$ of a graph $\Gamma$, with adjacency matrix $A$, is a linear combination of $A$, the diagonal matrix $D$ of vertex degrees, the identity matrix $I$, an…