•Eigenvectors of adjacency matrices of
graphs give good (Huckel) approximations to wave functions

•The largest nontrivial eigenvalue of a
regular graph gives a measure of how close the graph is to being disconnected

•“Expander Graphs” – those with a large
separation (spectral gap) between the trivial and nontrivial eigenvalues -- are highly
desirable

•Expander graphs have important theoretical applications, as well as
emerging cryptographic utility

Conclusions