FOM: confusion

Harvey Friedman friedman at math.ohio-state.edu
Tue Mar 2 18:12:38 EST 1999


Response to McLarty 4:31PM 3/2/99.

Are are still confused on some basic material, despite the fact that
several of us having taken the time to correct you?

You wrote, yet again!:

> My example was:
>
>         "If T is a finitely axiomatized fragment of ZFC, then ZFC
>        proves Consis(T)".
>
>Like nearly all logicians, I believe that quoted assertion, which can
>obviously be expressed in ZFC.

Not only can this quoted assertion be expressed in ZFC, it is actually
easily proved in ZFC. In fact, it is easily proved within EFA = exponential
function arithmetic.

>I cannot make the infinitely many separate
>ZFC verifications for each finitely axiomatized fragment T, but I've seen
>the  familiar inductive proof which cannot be formalized in ZFC.

The "familiar inductive proof" of what? The assertion

If T is a finitely axiomatized fragment of ZFC, then ZFC
>        proves Consis(T)".  ??

This has a perrectly familiar inductive proof which can be formalized in
ZFC, or even EFA - as I keep telling you.





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