The normalized Laplacian spectrum of quadrilateral graphs and its applications

The quadrilateral graph Q(G) of G is obtained from G by replacing each edge in G with two parallel paths of lengths 1 and 3. In this paper, we completely describe the normalized Laplacian spectrum on Q(G) for any graph G. As applications, the significant formulae to calculate the multiplicative degree-Kirchhoff index, the Kemeny's constant and the number of spanning trees of Q(G) and the quadrilateral iterative graph Qr(G) are derived.