Fig. 4.3.
Classification of treatment-response as a function of θ and r when b > d. q = 0, s = 0.001, b = 0.9, d = 0.5. Regions are labelled according to the dynamics observed under treatment, assuming the dynamics were at equilibrium prior to treatment. In the bistable region, both the disease-free and total-infection stationary solutions are locally stable under treatment. The boundaries between the regions of strong delay, weak delay, and no delay are fuzzy, in the case of θ = 1, and the boundaries are even fuzzier for θ < 1. In the sliver between the dotted line and the solid line defining the bistable region our approximation to td in Eq. (4.8) fails because there is no nearby stationary solution to use for u* (see Fig. 4.4). In this sliver, the approximation method described in Appendix C can be used.