 Figure 15: Three diagrams showing how, as the amount of correlation among interactions increases, fair division is more likely to evolve. In figures 15(a) and 15(b), there is an unstable fixed point in the interior of space where all three strategies are present in the population. (This is the point where the evolutionary trajectories appear to intersect.) This fixed point is what is known as a saddle point in dynamical systems theory: the smallest perturbation will cause the population to evolve away from that point to one of the other two attractors.