  Sensitivity studies the network response to perturbations. We consider local
perturbations of the concentrations of metabolites at an equilibrium. We
investigate the responses in the network, both of the metabolite concentrations
and of the reaction fluxes. Our approach is purely qualitative, rather than
quantitative. In fact, our analysis is based, solely, on the stoichiometry of
the reaction network and we do not require any quantitative information on the
reaction rates. Instead, the description is done only in algebraic terms, and
the only data required is the network structure. Biological applications
include metabolic control and network reconstruction.
