... CA can be understood. The application of computational mechanics to the understanding of rules evolved by the GA is discussedfurther in Crutchfield and Mitchell 1994, in Das, Mitchell, and Crutchfield ... proportional to fitness, the rules are ranked and selection is done at random from the top 20% of the population. Moreover, all of the top 20% are copied without modification to the nextgeneration, and ... takes two arguments, and A is a terminal. Notice that the argument to a function can be the resultof another function—e.g., in the expression above one of the arguments to the top−level * is (*...