A new approach for constructing graph being determined by their generalized $Q$-spectrum

Abstract

Given a graph $G$, we have the adjacency matrix $A(G)$ and degree diagonal matrix $D(G)$. The $Q$-spectrum is the all eigenvalues of $Q$-matrix $Q(G)=A(G)+D(G)$. A class of graphs is determined by their generalized $Q$-spectrum (DGQS for short) if any two graphs among the class have the same $Q$-spectrum and so do their complement imply that they are isomorphic. In [11], the authors provides a new way to construct $DGQS$ graphs by considering the rooted product graphs $G\circ P_k$ and they prove when $k=2,3$, $G\circ P_k$ is $DGQS$ for a special graph $G$. In this paper, we will prove that under the same conditions for $G$, the conclusion is true for any positive integer $k$.