Systems of interacting species, such as biological environments or chemical reactions, are often described mathematically by sets of coupled ordinary differential equations. While a large number
of species may be involved in the coupled dynamics, often only
species are of interest or of consequence. In this paper, we explored how to construct models that include only those given
species, but still recreate the dynamics of the original
-species model. Under some conditions detailed here, this reduction can be completed exactly, such that the information in the reduced model is exactly the same as the original one, but over fewer equations. Moreover, this reduction process suggests a promising type of approximate model—no longer exact, but computationally quite simple.