(06/06/2022, 04:00 PM)MphLee Wrote: Unless I'm the one confused here, it might be, I suggest to NOT confuse circulation/omegation with FGHs.Why is the operation a circulated to the b not well defined? Two circulated to the two still equals four. Two circulated to the five may be some large infinity. Still defined.
The omega in omegation/circulation is NOT an ordinal. It is just notation sugar, it has nothing to do with the ordinal omega. Also the operation \(o(a,b)=\lim a\uparrow^n b\) is not even well defined, let alone taking superfunctions out of it.
Also the point of FGH is that they extend Ackermann-Goodstein \(a\uparrow^n b\) like functions from \(n\in\mathbb N\) to \(n\in {\bf On}\), but not to all the ordinals but only to sufficiently small ones, i.e. transfinite ordinal that must be countable \(|\alpha|\leq\aleph_0\), and are also recursively definable in some technical sense (or you can compute the fundamental sequences).
Also there is not a single way to extend it to transfinite ordinals, but multiple ways to do it, some more natural than others, and all the various ways depend fundamentally on a choice of a system fundamental sequences. A fundamental sequence is a system of choices about how to define it for limit ordinals, and to my limited knowledge, it amounts to an algorithm of diagonalization. In other words \(a\uparrow^\omega b\) has not really something to do with the idea of infinity or limit but it is defined using a trick, something like defining \(a\uparrow^\omega b=a\uparrow^b b\).
Not all of the levels of the Fast-growing hierarchy are recursive. Not all countable ordinals have computable fundamental sequences even if they recursive ordinals. The Church-Kleene ordinal (https://googology.fandom.com/wiki/Church-Kleene_ordinal) for instance, is non recursive and non computable.
It might be interesting to extend the hyper-operation hierarchy to transfinite ordinal ranks.
I wonder how omega minus one would behave in some sort of extension of the Fast-growing hierarchy. I know omega minus one is not an ordinal. But it is a Hyperreal number.
Please remember to stay hydrated.
ฅ(ミ⚈ ﻌ ⚈ミ)ฅ Sincerely: Catullus /ᐠ_ ꞈ _ᐟ\
ฅ(ミ⚈ ﻌ ⚈ミ)ฅ Sincerely: Catullus /ᐠ_ ꞈ _ᐟ\

