Scaling limits of spatial chemical reaction networks

We study the effects of fast spatial movement of molecules on the dynamics of chemical species in a spatial heterogeneous chemical reaction network. The reaction networks we consider are either singleor multiscale. When the dynamics is on a single-scale, fast spatial movement has the single effect of averaging the dynamics over the distribution of all the species. However, when the dynamics is on multiple scales our findings show that the spatial movement of molecules has different effects depending on whether the movement of each type of species is faster or slower then the effective dynamics of the reaction system on this molecular type. We assume the reaction dynamics separates into a fast subsystem of reactions with a stable stationary probability measure and a slow subsystem on the time scale of interest. We obtain results for both the case when the fast subsystem is without and the case with conserved quantities, where a conserved quantity is a linear combination of fast species evolving on a slower timescale.