Alan J. Hoffman, The Change in the Least Eigenvalue of the Adjacency Matrix of a Graph Under Imbedding, SIAM Journal on Applied Mathematics, Vol. 17, No. 4 (Jul., 1969), pp. 664-671 ...

Interest has centred recently on the application of the theory of directed graphs to social networks. Graph theory provides a vocabulary and a set of measures which enable the formal properties of a ...