Figure 5.

(a–d) Comparison of the ‘incurable’ area for the MTD-based policy versus the adaptive policy. Unlike the MTD-based treatment, adaptive policies lead to a patient recover from most initial states even with a small $d_{\max }.$ The blue colour indicates initial states from which the recovery is achievable. The green colours represent initial states from which the recovery is impossible (i.e. the ‘incurable’ area): the light green—trajectories eventually get into the failure zone; the dark green—trajectories are cyclic and cannot cross either the recovery or failure barriers. (Online version in colour.)