Figure 4.4.

System (1.2) with 50-50 treatment, i.e., when $f_a=f_b=\frac{1}{2}$, f_ab = 0, we choose the same parameters Λ = 10, d = 1, b = 1, q = 0.1, s = 0.3, c = 1.5, h = 0.2, the same initial values x(0) = 0.45, y_w (0) = 0.35, y_a (0) = 1.4, y_b(0) = 0.9, y_ab(0) = 2.6, and let r_w, r_a, r_b, r_ab and h vary such that R₀ > 1. (i) When r_ab < min{r_w + h, r_a + h/2, r_b + h/2}, the semitrivial equilibrium E_ab is stable;(ii) when r_a + h/2 < min{r_w + h, r_b + h/2, r_ab }, the semitrivial equilibrium E_a,ab is stable; (iii) when r_b + h/2 < min{r_w + h, r_a + h/2, r_ab}, the semitrivial equilibrium E_b,ab is stable; (iv) when r_w + h < min{r_a + h/2, r_b + h/2, r_ab}, the positive equilibrium Ẽ is stable.