Dynamical evolution of a cluster of primordial black holes
  Evolution of a cluster of primordial black holes in the two-body relaxation
approximation based on the Fokker-Planck equation is discussed. In our
calculation, we consider the self-gravitating cluster with a wide range of
black holes masses from $10^{-4} M_{\odot}$ up to $100 M_{\odot}$ and the total
mass $10^5 M_{\odot}$. Moreover, we included a massive black hole in the
cluster center which determines the evolution rate of the density profile in
its vicinity.
