User blog comment:Ikosarakt1/Symbols function/@comment-25418284-20121205235359/@comment-5150073-20121217124206

I have seen Sbiis Saibian's article about recursion. He try to define it using only 4 fundamental functions:

Input-output: I(n) = n

Successor: S(n) = n+1

Predecessor: P(n) = n-1

Unity: u = 1

Successor function is also known as zeration, zeroth order operation, so we can't recurse it further.