Fig. 1.
The domain is decomposed into a deterministic region where the system is described by the mean field equations, and a stochastic region in which it is described by the stochastic equations. At the interface, which is a single compartment, between these domains the flux into the mean field domain is deterministic (equation (13)), whereas the reactions and flux into the stochastic domain are calculated in a stochastic way (equations (14) and (16)).