User blog comment:SuperJedi224/Question/@comment-5029411-20141124132603

Let \(\ss\) = x.

x(0) = 1

x(1) = phi(2,0)

x(2) = phi(phi(1,0)+1,0)

x(3) = phi(phi(phi(1,0)+1,0)+1,0)

x(w) can reach $$\Gamma_0$$.