I want to bound some functions using the fast-growing hierarchy, but for accounting reasons it looks like it's going to be easier to deal with a modified hierarchy that grows at "$1/\omega$-th" the rate: my first guess at the hierarchy I want is
- $f_0(x)=x+1$
- $f_{\lambda}(x)=f_{\lambda[x]}(x)$
- $f_{\lambda+n}(x)=f_\lambda^n(x)$
Has this, or perhaps some more carefully thought out version, appeared in the literature?