Re: Columns without names

From: Marshall <marshall.spight_at_gmail.com>
Date: 20 Sep 2006 19:02:48 -0700
Message-ID: <1158804168.012419.137730@i42g2000cwa.googlegroups.com>

vc wrote:
> paul c wrote:
> > >
> > > It depend on your favorite set theory. In some, R = {x | not( x in x)}
> > > does not exist, in others it does.
> > > ...
> >
> > I'm having a hard time seeing this - in what set theory would R = {x |
> > not( x in x)} exist?
>
> NBG.
Maybe I'm way off base here, but wouldn't the above not exist in any set theory with the Axiom of Regularity? So it wouldn't be a set in ZF, either.

Marshall Received on Wed Sep 20 2006 - 21:02:48 CDT