Fig. 5

The PSS approximation of the multistationarity region for the network in Fig. 3a of degree 2 obtained by the information of Fig. 4c. The union of orange colored subrectangles is considered as the initial approximation of the multistationarity region obtained by the rectangular representation and chosen as the set K. The yellow colored area is the difference of \(U(p)-K\). Remember that the PSS representation of the multistationarity region is the yellow region which contains the orange rectangles as well