Occurence Probabilities of Stochastic Paths
  An analytical formula for the occurence probability of Markovian stochastic paths with repeatedly visited and/or equal departure rates is derived. This formula is essential for an efficient investigation of the trajectories belonging to random walk models and for a numerical evaluation of the `contracted path integral solution' of the discrete master equation [Phys. Lett. A 195, 128 (1994)]. 
Dirk Helbing and Rolf Molini