1. A method for measuring proximity of two nodes in a network, comprising: computing, by a processor, a candidate sub-graph of a portion of the network; determining, by the processor, a cycle free escape conductivity proximity of the two nodes in accordance with the candidate sub-graph, wherein the cycle free escape conductivity proximity is determined in accordance with a cycle free escape probability, wherein the cycle free escape probability is a probability that a random walk originating at one of the two nodes reaches another one of the two nodes without visiting any node in the network more than once; and extracting, by the processor, a proximity sub-graph in accordance with the cycle free escape conductivity proximity.