[FOM] eliminating AC

[Paul Levy]

>>> What is the simplest way to see that any arithmetical consequence  
>>> of ZFC is a consequence of ZF?

Is this true for second-order sentences too?  Sorry for the naive  
question.  I can see that it's not true for third-order sentences  
(assuming ZF consistent), since well-orderability of the continuum is  
third-order.

And I ask the same question for ZF+CH.

regards,
Paul





--
Paul Blain Levy
School of Computer Science, University of Birmingham
+44 121 414 4792
http://www.cs.bham.ac.uk/~pbl