## FANDOM

10,825 Pages

12H is a super fast-growing hierarchy.

## Defination

$$A_0(n)=\text{FOOT}(n) \\ A_{b+1}(n)=A^n_b(n)$$

$$A_{\alpha}(n)=A_{\alpha[n]}(n)$$ if and only if $$\alpha$$ is a limit ordinal.