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

NENASHI, Tegiri a écrit :

> "Cimode" <cimode_at_hotmail.com> wrote in news:1168250971.134073.316120
> _at_i15g2000cwa.googlegroups.com:
>
> >
> > David wrote:
> >> Consider the following relation
> >>
> >> person(P,M,F) :- person P has mother M, father F.
> >>
> >> By induction a non-empty
> >> database would have to be infinite.
> > A false premise makes all deductions coming from it false.
>
> It is not true. A false premiss permits any deduction. See the ex falso
> quodlibet doctrine. The classical logic respects the doctrine and Prolog
> is founded in classical logic.
Mmm...I guess I should have phrased that otherwise. I consider that all deductions coming from a false premise should be considered false until proven otherwise.

> >Closed
> > World Assumption does not say anything about the number of element that
> > belong to a domain of values from which one attribute values are
> > derived. In the case of a *person* domain, the number of elements in
> > the set is certainly finite. Therefore, the number of propositions
> > involving person as an attribute is limited as well.
> >
> >
Received on Mon Jan 08 2007 - 19:30:30 CET