Re: Nulls, integrity, the closed world assumption and events

Cimode wrote:
> David wrote:
> > Cimode wrote:
>
> > No. If we show p => q and p is false then we can't deduce q is false.
> Sure, but if proposition P is FALSE, we certainly even less deduce that
> Q would be TRUE. Which is exactly what you do by considering the
> person set in some hierarchy necessarily has an infinite number of
> elements. As I told you Closed world assumption does not allow you to
> make such inference....

You don't seem to understand my post. I don't argue for an infinite domain at all - on the contrary we both agree it must be finite. If

    p => infinite domain

then by assumption of a finite domain and contra-positive we deduce not p.

> > My point is that the following six conditions can't all be satisfied at
> > once
> > C1. use person(P,M,F) relation
> > C2. don't allow nulls in M,F
> > C3. enforce referential integrity on M,F
> > C4. only allow finite number of persons in the domain
> > C5. there are no cycles in the family tree
> > C6. there is at least one person
> >
> > Obviously we must have C4, C5 and allow C6. I suggest that C2,C3 are
> > important and therefore C1 should be dropped. ie the person(P,M,F)
> > relation itself is "bad". Do you agree?

> I agree or disagree to points that make sense. I do not see sense in
> the point you're trying to make...

Do you agree that C1-C6 can't all be satisfied at once? Received on Mon Jan 08 2007 - 14:32:08 CET