[FOM] Feferman's natural well-ordering problem.

mario chiari.hm at flashnet.it
Sat Feb 4 04:23:52 EST 2006


Michael Rathjen has a very nice introductory paper on so called Ordinal
Analysis. See at:

(Rathjen`s preprints).

Stan Wainer is at Leeds too, but I don`t see the draft William Tait is
pointing to:

mario chiari

On Thu, 2006-02-02 at 15:15 -0600, William Tait wrote:
> On Feb 1, 2006, at 10:33 PM, Bill Taylor wrote:
> > This was mentioned by Andreas Weierman the other day, and I can  
> > find no
> > help on Googol for it.
> >
> > Can someone please explain what it is, for us?
> The proof theoretic strength of a formal subsystem of second-order  
> number theory is sometimes measured by the LUB of the ordinals alpha  
> for which (suitably formulated) transfinite induction up to alpha or  
> definition by transfinite recursion up to alpha can be derived in the  
> system.

> Kind regards,
> Bill Tait

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