- From: Pat Hayes <phayes@ihmc.us>
- Date: Fri, 7 May 2004 12:48:41 -0500
- To: "Rob Shearer" <Rob.Shearer@networkinference.com>
- Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
- Message-Id: <p06001f2cbcc17a761078@[10.0.100.76]>
> > Where in my requirement does it say "just a little bit of inference"? >> Where does it imply it? I must have missed that bit. :> >> >> And, besides, charter thwack: >> >> 1.8 Derived Graphs >> >> The working group must recognize that RDF graphs are often >> constructed by aggregation from multiple sources and through logical >> inference, and that sometimes the graphs are never >> materialized. Such graphs may be arbitrarily large or infinite. > >We've been through this before, and I'm getting a bit tired of it. >This sentence seems to be pointing out exactly what I've been saying: we >can't standardize an implementation because implementations will have >very different requirements depending on how they get their knowledge >about the underlying data model. >This paragraph even seems to make explicit that we're meant to be >addressing how we query a graph, not some of the particular ways to form >that graph from. >If you've got some RDF and some RDFS, then there are two quite >reasonable graphs: the raw RDF the way it's written, and a "completed" >graph which has a whole bunch of inferred triples. Right, exactly. In fact there are quite a number of these. >(There are also a >number of other graphs which can be derived from this data set in other >ways, such as the possible graphs, the impossible graphs, the graphs >with the directions of all edges reversed, the interesections or unions >of any of these other graphs, etc.) Yes, but lets keep things in perspective. How about only considering valid derivations from the basic graph, and maybe even requiring a closure relative to some subset of the complete set of rdfs rules: http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#RDFSRules >An implementation should have the freedom to interpret a query against >any of these "virtual" graphs, thus we cannot specify how an >implementation operates. No, but what we could consider is ways for the query to indicate which virtual graph it is intended to be aimed at. A server might just keep one base graph but treat the query differently if it indicates it is aimed at the closure under transitivity of rdfs:subClassOf, for example (rules rdfs6 and rdfs9). > >> > What's more, adding support for just one particular flavor of >> > supplementary semantic knowledge (RDFS) is great way to >> kill off use of >> > any other knowledge sources. >> >> Uh... RDFS is hardly "one particular flavor of supplementary semantic >> knowledge". That's about as perverse a description as I can >> imagine. Besides, if you're worried about "killing off" OWL, that's an >> argument to do RDFS in 1.0 and OWL in 2.0, not an argument not to do >> RDFS at all. > >I think it's quite clear that sucking every possible type of querying >into our specification is about the worst way to write a standard >possible. >The fact that inferencing is very useful is an excellent reason to make >sure our query language is compatible with use where RDF is the data >model on which inferencing occurs. >The fact the inferencing is a complex and open-ended problems and that >we could not possibly address it (because the basic semantic encodings >are still being standardized) is a pretty incontrovertable argument that >we can't solve the inferencing problem. I think that's a good reason not >to try. Well, up to RDFS at least there is a complete set of rules which are pretty transparently related to the formal semantics, if we want to use them. > >Let's leave derived graphs and inferencing to working groups that know >how to address them and confine ourselves to representing queries >against the data model which underlies it all. Im sympathetic to this pov, however. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Friday, 7 May 2004 13:49:09 UTC