Fig. 8.

Example of dependence of system (9) on k. We consider the system (9) with Pr₁ = (ξ₁, ξ₂, λ, k, β) = (1, 1, 1, 1, 2) (solid lines) and ${\mathbf{Pr}}_1^{\ast }=({\xi }_1,{\xi }_2,\lambda ,k,\beta )=(1,1,1,2,2)$ (dashed lines) and plot M (green) and $M_l^{\ast }$ (red). R₁ represents the tumor substainability region in the phase space for ${\mathbf{Pr}}_1^{\ast }$, but the Allee region for Pr₁. Conversely, R₂ represents the tumor sustainability region for Pr₁, but the Allee region for ${\mathbf{Pr}}_1^{\ast }$ (Color figure online)