Bianconi$-$Barabsi Model

Consider the Bianconi$-$Barabsi model with two distinct fitnesses, $=$ a and $=1.$ To be specific, let us assume that the fitness follows the double delta distribution

$()=12($a$)+12(1)$with$0$a$1$

Calculate the degree exponent, and its dependence on the parameter a$.$

Calculate the stationary degree distribution of the network.