- From: Wagner, G.R. <G.R.Wagner@tm.tue.nl>
- Date: Tue, 18 Nov 2003 15:35:02 +0100
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, <stefan@ISI.EDU>
- Cc: <www-rdf-rules@w3.org>
> Not so fast. What if it is difficult to determine just what objects > (belonging to a particular class) exist? Then what does > closing (a class) mean? There are two issues: 1) Closing a class/predicate, such as with N3's "definitiveDoc" declaration. In such a case (of typically administrative information) you don't have to deal with indefinite information and applying NAF to such a predicate corresponds to classical negation. 2) The semantics of NAF in the presence of indefinite information: in this case there are still some research issues concerning the proper concept of preferred/"minimal" model, but clearly NAF(P(a)) fails (cannot be inferred) on the basis of P(a) v P(b). -Gerd
Received on Tuesday, 18 November 2003 14:25:43 UTC