- From: Enrico Franconi <franconi@inf.unibz.it>
- Date: Mon, 9 Jan 2006 14:31:19 +0100
- To: Dave Reynolds <der@hplb.hpl.hp.com>
- Cc: Jos de Bruijn <jos.debruijn@deri.org>, public-rif-wg@w3.org
On 5 Jan 2006, at 15:51, Dave Reynolds 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. A a naive gensym would fail the use case <http://www.w3.org/2005/ rules/wg/wiki/Managing_incomplete_information>, where two examples (in section "9.4. (Rules involving generation of unknown)") show how you can make things wrong with a naive use of skolem constants to implement the existential variables in the head. cheers --e.
Received on Monday, 9 January 2006 13:31:34 UTC