  Motivated by recent progress on the interplay between graph theory, dynamics,
and systems theory, we revisit the analysis of chemical reaction networks
described by mass action kinetics. For reaction networks possessing a
thermodynamic equilibrium we derive a compact formulation exhibiting at the
same time the structure of the complex graph and the stoichiometry of the
network, and which admits a direct thermodynamical interpretation. This
formulation allows us to easily characterize the set of equilibria and their
stability properties. Furthermore, we develop a framework for interconnection
of chemical reaction networks. Finally we discuss how the established framework
leads to a new approach for model reduction.
