Eigenvector centrality is one method of computing the
"centrality", or approximate importance, of each node in a
graph. The assumption is that each node's centrality is the sum
of the centrality values of the nodes that it is connected to.
The nodes are drawn with a radius proportional to their
centrality. The adjacency matrix and centrality matrix for the
solution are shown. The centrality matrix is an eigenvector of
the adjacency matrix such that all of its elements are positive.