Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math.independent

Topic: Inconsistency
Replies: 19   Last Post: Apr 28, 2012 2:28 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Frederick Williams

Posts: 2,166
Registered: 10/4/10
Re: Inconsistency
Posted: Apr 22, 2012 12:34 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Nam Nguyen wrote:
>
> On 22/04/2012 7:36 AM, Jan Burse wrote:
>

> >
> > Undecidable theories such as ZFC in general
> > don't admit a k.

>
> How would you know ZFC is undecidable in the first place?


A simple argument is as follows.
FOL with a single binary predicate is undecidable. (See Church, Turing,
and um... was it Kalmar?) And since ZFC is built on FOL with a single
binary predicate it is undecidable.

A better argument is to show that recursive functions are representable
in ZFC and proceed as you would in Robinson's Q or whatever. I say
'better' because that way the result about FOL with a single binary
predicate is a simple corollary.

--
When a true genius appears in the world, you may know him by
this sign, that the dunces are all in confederacy against him.
Jonathan Swift: Thoughts on Various Subjects, Moral and Diverting



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2013. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.