ISOMORPHISM OF GRAPHS.

Several authors have discussed whether a graph is characterised by the values of its adjacency matrix. It is thought that the characteristic polynomial, ie, determinant of the characteristic matrix obtained from adjacency matrix, should be adequate to detect isomorphism between graphs. However, examples of non-isomorphic graphs whose adjacency matrices have the same characteristic polynomials have been found through computer search. Further, computation of characteristic polynomials for larger graphs is difficult and a computer is needed. In this paper different criteria, concept and computation of which are easy, are proposed to detect isomorphism.