Fig. 4.5.

Side-by-side comparison of contour plots of the treatment t_d using numerical solution of system (2.7) (left) and the Formula (4.8) derived from the linear approximation (right). The approximate bound on bistability, $\text{r}=\text{d}+\frac{\text{d}}{(1-\theta )\text{b}}$, labeled ∞, is the same in both plots. Contour heights are 10, 20,100 and ∞. Parameter values d=0.5, b=1, s=10⁻³, q=0.θ_c=0.5 when r=0 in both plots.