- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Fri, 3 Sep 2004 11:02:26 +0100
- To: "Eric Prud'hommeaux" <eric@w3.org>, "RDF Data Access Working Group" <public-rdf-dawg@w3.org>
-------- Original Message -------- > From: Eric Prud'hommeaux <> > Date: 2 September 2004 01:00 > > On Fri, Aug 27, 2004 at 10:28:40AM +0100, Steve Harris wrote: > > > > On Thu, Aug 26, 2004 at 06:37:58 +0100, Andy Seaborne wrote: > > > My next example (3) then highlights an interaction of SOURCE and > > > inference if we attempt to use the natural result from case 2. > > > Others advocate that SOURCE reflect the origin graph in the > > > aggregation. What if it can arise across the aggregations? Are we > > > saying that inference *can't* be done in this case? > > > > I havent seen anyone else argue for inferred triples being the the > > graph of one of the ground triples that lead to the inference. It > > seems like an odd decision. > > > > If you place inferred triples in another SOURCE/graph (which seems > > reasonable to me) then these problems go away. > > > I propose that we not worry about where the inferences go -- leave > that to the various engines. A different name for the RDFS/OWL closure, and closure of the merged union, is fine by me. We just need to be clear. > They can associate them with whatever > URI or bnode they want. Further, they can add a bunch of proof > properties if they want. Some group can define those properties > after they've been better explored, just as they could say that > > SOURCE ?foo (?p ?s ?o) > really means ?rt rdf:type rdf:Statement . > ?rt rdf:predicate ?p. > ?rt rdf:subject ?s. > ?rt rdf:object ?o. > ?rt rdf2:label ?foo. Having "named containers" (see rdf-interest discussion) is interesting. Are you proposing that SOURCE exactly equivalent to writing the triple patterns? [ Changing to s-p-o order everywhere, using some URIs] If SOURCE <foo> (?s <p> <o>) matches, does (?rt rdf2:label <foo>) match on its own? does (?rt rdf2:label <foo>) match if there is no SOURCE in the query? I'd hope that if the SOURCE clause is removed, it shouldn't change whether some triple pattern matches even involing the rdf2:label vocabulary. What about: ( ?rt rdf:subject ?s ) ( ?rt rdf:predicate <p> ) ( ?rt rdf:object <o> ) Does this match even if there is no SOURCE? If so, seems like we are requiring always-reification in all query implementations and stores. We may be able to explain SOURCE in this way but a more direct framework of named containers might be clearer. Andy > > By defining a syntax by which our language gets at this provenance > data, we get to duck the hard questions of how that provenance data > projects into the RDF world. Call me a coward, but that seems like > a good idea to me. > -- > -eric > > office: +81.466.49.1170 W3C, Keio Research Institute at SFC, > Shonan Fujisawa Campus, Keio University, > 5322 Endo, Fujisawa, Kanagawa 252-8520 > JAPAN > +1.617.258.5741 NE43-344, MIT, Cambridge, MA 02144 USA > cell: +1.857.222.5741 (does not work in Asia) > > (eric@w3.org) > Feel free to forward this message to any list for any purpose other than > email address distribution.
Received on Friday, 3 September 2004 10:02:59 UTC