I have a small question regarding the following problem:
Suppose that newborn nodes come in groups of n in each period. Suppose that they attach a fraction f of their links uniformly at random to other newborn nodes, and a fraction 1 − f to older nodes via preferential attachment. Using a continuous time mean-field approximation, develop an expression for the degree distribution. m represents the number of links made by each newborn node.
However, one of the things I am unsure about is why the number of links each newborn forms with another newborn node is $$m(1+f)$$
Why not $$mf$$
I understand that the number of links to each older node is $$m(1-f)n$$
Unsure on this small detail.
Many thanks.