[FOM] Real Division Algebras + Tarski/Lefschetz Principles

[Adam Epstein]

On Tue, 10 Sep 2002, Robert M. Solovay wrote:
> >
> ? I know that Classical Analysis is conservative over
> > PA.
> 
> 	This is not correct. "Classical analysis" = "Second-order number
> theory" proves Con(PA).
> 

Thanks for the clarification. I do remember looking over a monograph of
Takeuti which seems to reconstruct a fair amount of Classical Analysis as
a conservative extension of PA. But I guess I'm not even sure what CA
officially means. In any event, this gives a bit more content to the
question about Hopf's Theorem.

AE