| The theory of graph spectra is an active and important field in graph theory, dis-tance spectra and distance signless laplacian spectra of graphs is also an important field in the theory of graph spectra.In this thesis, we mainly discuss some problems on the distance spectral radii and distance signless laplacian spectral radii of tricyclic graphs on n vertex. The main contents of the thesis are as follows:We mainly introduce the development of graph theory and graph-spectral theory, the research background of this thesis and some basic terminologies and notations of graph theory and graph spectral theory in chapter one. We introduce some fundamental lemmas and the classification of tricyclic graphs in chapter two. We characterize tricyclic graphs with minimum, second-minimun and third-minimun distance spectral radii in chapter three. We characteriz tricyclic graphs with minimum, second-minimun and third-minimun distance signless laplacian spectral radii in chapter four. We primarily summarize the main conclusions of the thesis and give some considerable problems for further study in chapter five. |
