In the BA model, new nodes are added to the network one at a time. Each new node is connected to <math>m</math> existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability ''p''<sub>''i''</sub> that the new node is connected to node ''i'' is<ref name=RMP>{{Cite journal | In the BA model, new nodes are added to the network one at a time. Each new node is connected to <math>m</math> existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability ''p''<sub>''i''</sub> that the new node is connected to node ''i'' is<ref name=RMP>{{Cite journal |