A generalized inverse for graphs with absorption

We consider weighted, directed graphs with a notion of absorption on the vertices, related to absorbing random walks on graphs. We define a generalized inverse of the graph Laplacian, called the absorption inverse, that reflects both the graph structure as well as the absorption rates on the vertices. Properties of this generalized inverse are presented, including a basic relationship between the absorption inverse and the group inverse of a related graph, a forest theorem for interpreting the entries of the absorption inverse, as well as relationships between the absorption inverse and the fundamental matrix of the absorbing random walk. Applications of the absorption inverse for describing the structure of graphs with absorption are given, including a directed distance metric, spectral partitioning algorithm, and centrality measure.