  In this paper, we abstract a kind of stochastic processes from evolving
processes of growing networks, this process is called growing network Markov
chains. Thus the existence and the formulas of degree distribution are
transformed to the corresponding problems of growing network Markov chains.
First we investigate the growing network Markov chains, and obtain the
condition in which the steady degree distribution exists and get its exact
formulas. Then we apply it to various growing networks. With this method, we
get a rigorous, exact and unified solution of the steady degree distribution
for growing networks.
