A note on the graph’s resolvent and the multifilar structure

We consider the recently discovered V. Ejov, J.A. Filar, S.K. Lucas, P. Zograf, Clustering of spectra and fractals of regular graphs, J. Math. Anal. Appl. 333 (2007) 236-246] threadlike structure of the plot representing d-regular graphs in the mean-variance coordinates of exponential sums of the graph spectra. In this note we demonstrate that this self-similar phenomenon is more ubiquitous by exhibiting it with the help of a different generating function, namely the mean and the variance of the resolvent of the adjacency matrix of the graph. We also discuss the location of non-Hamiltonian graphs within this geometric structure.