Gerhard Keller and Carlangelo Liverani 

Rare events, escape rates and quasistationarity:  some exact formulae.
          
  
                           ABSTRACT
                                           
We present a common framework to study decay and exchanges rates in a wide 
class of dynamical systems. Several applications, ranging form the metric 
theory of continuons fractions and the Shannon capacity of contrained 
systems to the decay rate of metastable states, are given.