- From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Date: Mon, 15 Sep 2008 12:38:35 +0100
- To: W3C OWL Working Group <public-owl-wg@w3.org>
We had quite a long discussion about this during last week's teleconf [1], and I was hoping for some followup via email. To kick things off, I have attempted to summarise the discussion below. No doubt the protagonists will correct me if I (unintentionally) misrepresented what they were saying. Ian Zhe: Adding triple will ease burden on implementers Boris: May be mapping issues; what to do with an RDF doc that includes a reified triple without the corresponding base triple? Not likely to occur often in practice, so not much burden. Michael Schneider: More stable without added triples; may not be possible to add to ontologies where we don't have write permission; might cause problems with axiom closure; not in favour. Alan: doesn't see a problem with missing base triple, or with issues raised by Michael; issue is with monotonicity rather than performance. Boris: OWL RL reasoner would miss inferences without base triple; no guarantee that it will be included; regarding monotonicity, OWL Full semantics entail base triple from reified one. Peter: Alan's example not non-monotonic. Zhe: still wants to stress performance; doesn't want to check information on all triples; what if there is a mixture of annotated and not -- do we forget the ones without annotations. Mike Smith: Such axioms are structurally different; spec already deals with this. Boris: Possible solution is to suggest "physical proximity" of reified triples and have parser add base triple. Alan: RDF pipes could be a problem. Boris: Doesn't see this. Peter: On performance, I/O cost of larger files may outweigh increased cost of de-reification rule. [1] http://www.w3.org/2007/OWL/meeting/ 2008-09-10#Issue_144___28_Missing_base_triple_in_serialization_of_axioms _with_annotations__29_
Received on Monday, 15 September 2008 11:39:27 UTC