ADJACENCY MATRIX

Adjacency matrix - The n by n binary matrix, say A, to represent node adjacency in a simple graph : A(i,j)=1 if node i is adjacent to node j. In the undirected case, A is symmetric. In the directed case, the adjacency means there is an arc from i to j. In the case of a multigraph , A(i, j) = number of edges whose endpoints are nodes i and j.