Generalized distance spectral characterizations of graphs based on Smith Norm Form.

"Which graphs are determined by their spectra (DS for short)?" is an important and challenging topic in spectral graph theory. Let G be an n -vertex graph with adjacency matrix A (G) and adjacency walk matrix W A (G) = [ e , A (G) e , ... , A n − 1 (G) e ]. We call G controllable if the rank of W A (G) is n over R and noncontrollable otherwise. In Wang (2017), the author gave a simple condition for a controllable graph to be determined by their generalized adjacency spectrum (DGAS for short). However, the result fails for noncontrollable graphs. In this paper, we consider the problem in the context of the generalized distance spectrum. Let G be a connected graph with distance matrix D. A graph G is determined by its generalized distance spectrum (DG D S for short) if any graph H sharing the same generalized distance spectrum with G must be isomorphic to G. The paper aims to extend the result in Wang (2017) from generalized adjacency spectrum to generalized distance spectrum. Besides, a simple arithmetic criterion is given to determine whether a connected graph is DG D S or not, which is applicable to some kind of noncontrollable graphs, e.g., regular graphs. [ABSTRACT FROM AUTHOR]