Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
Drexel University or The Math Forum.
|
|
|
|
Re: A natural theory proving Con(ZFC)
Posted:
Feb 11, 2013 12:25 PM
|
|
On Feb 8, 9:33 am, Zuhair <zaljo...@gmail.com> wrote:
> On Feb 8, 4:27 pm, Frederick Williams <freddywilli...@btinternet.com>
> wrote:
>
> > Zuhair wrote:
>
> > > I see the following theory a natural one that proves the consistency
> > > of ZFC.
>
> > > Language: FOL(=,in)
>
> > How do you express Con(ZFC) in that language? I know one can encode it
> > using names of sets rather as one can encode Con(PA) using numerals, but
> > isn't it rather hard work and is your claim justified without at least
> > an outline?
>
> The language of this theory is the same language of ZFC. Consistency
> of ZFC would be proved by constructing a model of ZFC in this theory,
> the class of all well founded sets in this theory is a model of ZF and
> ZFC simply follows.
Who will bell the cat?
C-B
> Note: if one desires a direct way to prove choice and global choice,
> then the last axiom can be replaced by the following:
>
> Universal limitation: x strictly < W -> set(x).
>
> where "strictly <" refers < relation with absence of bijection, W is
> the universal class of all sets.
>
> Note: we can also use the ordinary relations defining subnumerousity
> after injections instead of surjections used here and this would also
> be enough to prove Con(ZFC).
>
> Zuhair
|
|
|
|
