Feasible Equilibrium in Kinetic Systems*

In this note we link network deficiency with bifurcation theory. In fact we find out that network deficiency determines the class of equilibrium multiplicity. For deficiency one networks a saddle-node bifurcation with respect to mass inventory is the only route to multiplicity whereas for higher deficiencies alternative routes exist which may include pitchfork bifurcation. Interestingly, some kinetic networks within this class are capable of multiple equilibrium for any reaction simplex.