Evolution requires progression, not merely moving from any one genome to any other genome. In this case, then, we need a progressive series of genomes to form a valid pathway.

If all the k permutations of a genome can be ordered according to fitness, we will have k levels of fitness through which progression is possible. (Of course, there may be many groups of permutations at the same level, but for now we’ll assume k levels to keep it simple.) Here we’ll use the same type of analysis as before with points g_0 and g_k.