  Material balance equations describe the dynamics of the species in open
reaction systems and contain information regarding reaction topology, kinetics
and operation mode. For reaction systems, the state variables (the numbers of
moles, or concentrations) have recently been transformed into decoupled
reaction variants (extents of reaction), and reaction invariants (extents of
flow) (Amrhein et al., AIChE Journal, 2010). This paper analyses the conditions
under which an open homogeneous reaction system is cooperative in the extents
domain. Further, it is shown that the dynamics of the extents of flow exhibit
cooperative behavior. Further, we provide the conditions under which the
dynamics of the extents of reaction exhibit cooperative behavior. Our results
provide physical insights into cooperative and competitive nature of the
underlying reaction system in the presence of material exchange with
surrounding (i.e., inlet and outlet flows). The results of the article are
demonstrated via examples.
