Many fixed points, one least

Add one more rule that is also true (N is odd when N + 1 is even):

Now the rules have two fixed points over num = {0, …, 5}:

	even	odd
①	{0, 2, 4}	{1, 3, 5}	all facts tracing back to even(0)
②	{0, 1, 2, 3, 4, 5}	{0, 1, 2, 3, 4, 5}	”extra” facts support each other

① is contained in ②, in fact it is the least fixed point, our intended answer.