Fig. 8

A gene expression network with an S-system kinetics that allows Hill terms and exhibits multistationary behavior, taken from [35, Figure 2]. a The ODE system of the network. The set of species is \(\lbrace X_1, X_2, X_3, X_4\rbrace\). Each equation \(dx_i/dt\) consists of two terms responsible for production and degradation of the species \(X_i\). The right hand side functions are not necessarily of a polynomial type, or even a rational function form. b The sampling and PSS representation of the multistationarity region of this network when all the parameters other than \(\beta _i, i=2,3,4\) are fixed to the values in (5) and the remaining three parameters renamed \(k_i, i=1,2,3\) vary in the cube \(B=[(3,1,10),(7,5,14)]\). The sampling representation consists of the orange color points and the PSS representation is the area between the two yellow colored surfaces