User blog comment:Tetramur/My thoughts about functions and numbers/@comment-44079442-20191229182611/@comment-37993808-20191229183826

> Rayo's function is probably on the level of f_{w_w^CK}.

Adam Goucher provided evidence that his xi function is growing approximately at fixed point of α -> f_{w_α^CK}. So, Rayo's function is even stronger.

> w_1 is the first uncountable ordinal

I know, actually. That's a problem.