Quanta Magazine: How to Triumph and Cooperate in Game Theory and Evolution

… The advantage to aa individuals in the fourth year is proportional to the square of the difference in their numbers from the equilibrium value of 0.16. As an example, if the proportion of aa individuals is 0.12 at the start of the fourth year, the advantage they possess will be four times what they would have had if their proportion had been 0.14. …