- From: Enrico Franconi <franconi@inf.unibz.it>
- Date: Mon, 9 Jan 2006 14:07:49 +0100
- To: Dave Reynolds <der@hplb.hpl.hp.com>
- Cc: Jos de Bruijn <jos.debruijn@deri.org>, Michael Kifer <kifer@cs.sunysb.edu>, W3C RIF WG <public-rif-wg@w3.org>
On 5 Jan 2006, at 16:36, Michael Kifer wrote: > Dave Reynolds <der@hplb.hpl.hp.com> wrote: >> On the question of bNodes in the head, I hear the argument that it >> is not >> sufficient to just treat these as new Skolem constants but my >> intuitive >> understanding of the issue is too weak. It would be really helpful if >> someone could construct a test case which demonstrates the >> difference in >> results that arise between correct treatment of bNodes in the head >> versus >> treatment as Skolem constants. In the concrete cases I've seen >> where bNodes >> are used in the head of rules they seem to be intended as a form of >> anonymous gensym - so the Skolem constant semantics may be the more >> practically useful interpretation. > > Exactly. This was precisely one of the points in our J. Data Semantics > paper, And you can find in the use case <http://www.w3.org/2005/rules/wg/ wiki/Managing_incomplete_information> two examples (in section "9.4. (Rules involving generation of unknown)") which show how you can make things wrong with a naive use of skolem constants. cheers -e.
Received on Monday, 9 January 2006 13:08:07 UTC