Coexistence States for Cyclic 3-Dimensional Systems

In Ecology, the evolution of the species size is modelled by systems of dif-ferential equations of the type ẋi = xi fi(t, x1,..., xn) 1 ≤ i ≤ n (1) where xi = xi(t) ≥ 0 is the size of the species i in the instant t. Dependin