In this paper we define extended corona and extended neighborhood corona of two graphs G 1 and G 2 , which are denoted by G 1 • G 2 and G 1 * G 2 respectively. We compute their adjacency spectrum, Laplacian spectrum and signless Laplacian spectrum. As applications, we give methods to construct infinite families of integral graphs, Laplacian integral graphs and expander graphs from known ones.

The paper establishes some new bounds for Randic and GA indices.

No abstract

No abstract