This will be a bit informal.Originally Posted by kennyb
First is the set of all infinite sequences of elements drawn
from and is the set of all sequences of elements
drawn from .
Now let then . Now we may write each of the
s in unary, that is is represented by s, but we will write them in unary+ as
Now map to such that consists of the unary+
repersentations of the s seperated by a single s. This map takes
one-one onto a subset of (in fact the sub-set where there are no
two consecutive s.
so with the earlier result: