  Two symmetrically coupled logistic equations are proposed to mimic the
competitive interaction between two species. The phenomena of coexistence,
oscillations and chaos are present in this cubic discrete system. This work,
together with two other similar ones recently published by the authors,
completes a triptych dedicated to the two-species relationships present in
Nature, namely the symbiosis, the predator-prey and the competition. These
models can be used as basic ingredients to build up more complex interactions
in the ecological networks.
