User blog comment:Boboris02/Boris's ultima function/@comment-24676271-20161104001226/@comment-24920136-20161104075344

FGH only works on limit ordinals that have a fundamental sequence

w_1 doesn't. But, while it is the first  uncountable ordinal, so is Ω, and  while f_{w_1}(100) doesnt work, f_{ψ(Ω)}(100) does.