Auxiliary digraph for computing flow based edge connectivity
If the input graph is undirected, we replace each edge (\(u\),`v`) with two reciprocal arcs (\(u\), \(v\)) and (\(v\), \(u\)) and then we set the attribute ‘capacity’ for each arc to 1. If the input graph is directed we simply add the ‘capacity’ attribute. Part of algorithm 1 in  .
 Abdol-Hossein Esfahanian. Connectivity Algorithms. (this is a chapter, look for the reference of the book). http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf