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Topic: A finite set of all naturals
Replies: 15   Last Post: Aug 17, 2013 3:10 AM

 Messages: [ Previous | Next ]
 Virgil Posts: 8,833 Registered: 1/6/11
Re: A finite set of all naturals
Posted: Aug 17, 2013 1:14 AM

Nam Nguyen <namducnguyen@shaw.ca> wrote:

> On 16/08/2013 1:33 PM, Virgil wrote:
> > In article <c10s09pu0gs0av09l4gfqrrpbdm5gj510n@4ax.com>,
> > quasi <quasi@null.set> wrote:
> >

> >> quasi wrote:
> >>>
> >>>
> >>> odd(x) <-> [x*y=2*z] -> Ew[y=2*w]

> >>
> >> to Nam:
> >>
> >> Since you've has already defined various versions of even(x),
> >> my above definition of odd(x) can be expressed more simply as:
> >>
> >> odd(x) <-> even(x*y) -> even(y)
> >>
> >> Doesn't that qualify as a "positive formula"?

>
> No. Like Ben's D2, it's a "negative" formula.
>

> >>
> >> quasi

> >
> > I like that one!

>
> If you say so. One of course can "like" anything as one wishes,
> including a "negative" formula.

If implication does not make it negative, which you seem to allow
elsewhere, wherein does your alleged negative appear in it?
--

Date Subject Author
8/15/13 Ben Bacarisse
8/16/13 Virgil
8/16/13 namducnguyen
8/16/13 antani
8/16/13 namducnguyen
8/16/13 Peter Percival
8/16/13 Peter Percival
8/16/13 Ben Bacarisse
8/16/13 quasi
8/16/13 quasi
8/16/13 Virgil
8/17/13 namducnguyen
8/17/13 Virgil
8/17/13 Peter Percival