- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Tue, 12 Aug 2008 13:44:52 -0400 (EDT)
- To: alanruttenberg@gmail.com
- Cc: public-owl-wg@w3.org
From: Alan Ruttenberg <alanruttenberg@gmail.com> Subject: Re: ACTION-178: What is ISSUE-116 (Axiomatic Triples for OWL R) about? Date: Tue, 12 Aug 2008 13:22:14 -0400 > > On Aug 12, 2008, at 11:31 AM, Peter F. Patel-Schneider wrote: > > > > > From: Alan Ruttenberg <alanruttenberg@gmail.com> > > Subject: Re: ACTION-178: What is ISSUE-116 (Axiomatic Triples for OWL R) about? > > Date: Tue, 12 Aug 2008 11:22:40 -0400 > > > >> On Aug 12, 2008, at 11:16 AM, Ivan Herman wrote: > >> > >>> Alan Ruttenberg wrote: > >>>> On Aug 12, 2008, at 11:02 AM, Michael Schneider wrote: > >>>>> Alan Ruttenberg wrote: > >>>>> > >>>>>> Is the assumption that in OWL R/Full that the only way in which one > >>>>>> determine entailments is to forward chain rules and then look in > >>>>>> the resultant triples for it? > >>>>> > >>>>> It's not an "execution semantics". Instead, there has to *exist* a > >>>>> finite sequence of rule applications, which leads from the LHS to the RHS > >>>>> (or an upper graph of the RHS). > >>>> OK. I'm then confused by Ian's comment about generating infinite > >>>> numbers of triples: > >>> > >>> But his comment _was_ justified. In > >>> > >>> http://www.w3.org/TR/rdf-mt/#RDFINTERP > >>> > >>> the number of axiomatic triples is infinite indeed, due to the rdf:_i > >>> terms. Herman ter Horst's trick of keeping it finite for a specific > >>> graph tries to get around that problem and thereby making it possible to > >>> do, eg, a forward chaining on a specific graph (with the caveat that > >>> PFPS just referred to in another mail:-( > >> > >> Yes, but my question to Michael was to this point. From what he says I > >> don't see that the theoretical existence of an infinite number of > >> triples necessitates their materialization by forward chaining. There > >> are other methods of using rules. > >> > >> -Alan > > > > Which of the other methods of using rules are germane to this > > discussion? > > I am trying to understand the underlying assumptions in this > discussion. If no other method of rule applications than forward > chaining are being considered and a solution to this issue should assume > a forward chaining rule engine that would be useful information. What > prompts the questions and comment were an earlier discussion in which it > was mentioned that JENA used a combination of forward and backwards > chaining. > > Therefore your question is one I would I would like answered as well, > but I am not the one to answer it. > > -Alan I don't see that any of the other methods for using rules are even potentially germane to this discussion, regardless of what JENA does. peter
Received on Tuesday, 12 August 2008 17:47:36 UTC