LAPLACIAN MATRICES OF GRAPHS - A SURVEY

Let G be a graph on n vertices. Its Laplacian matrix is the n-by-n mat rix L(G) - D(G) - A(G), where A(G) is the familiar (0, 1) adjacency ma trix, and D(G) is the diagonal matrix of vertex degrees. This is prima rily an expository article surveying some of the many results known fo r Laplacian matrices. Its six sections are: Introduction, The Spectrum , The Algebraic Connectivity, Congruence and Equivalence, Chemical App lications, and Immanants.