Explicit Lyapunov functions and estimates of the essential spectral   radius for Jackson networks
  A family of explicit Lyapunov function for positive recurrent Markovian Jackson network is constructed. With this result we obtain explicit estimates of the tail distribution of the first time, when the process returns to large compact sets, and some explicit estimates of the essential spectral radius of the process. The essential spectral radius of the process provides the best geometric convergence rate to equilibrium that one can get by changing the transitions of the process in a finite set. 
Irina Ignatiouk-Robert and Danielle Tibi
math.PR