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

From: NENASHI, Tegiri <tnmail42_at_gmail.com>
Date: Mon, 8 Jan 2007 18:28:45 +0100 (CET)
Message-ID: <Xns98B27F2F66192asdgba@194.177.96.26>

"Cimode" <cimode_at_hotmail.com> wrote in news:1168250971.134073.316120 @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.

>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 - 11:28:45 CST