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 matrix forest theorem relating this generalized inverse to spanning forests of a related graph, 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 presented, including a directed distance metric, spectral partitioning algorithm, and centrality measure. 
Karly Jacobsen and Joseph Tien
math.CO