W3C home > Mailing lists > Public > semantic-web@w3.org > May 2006

Re: Grouing URIs - an RDF triple with multiple subjects

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 08 May 2006 16:20:07 -0400
To: Dan Brickley <danbri@danbri.org>
Cc: Phil Archer <parcher@icra.org>, semantic-web@w3.org, WCL-XG Public List <public-xg-wcl@w3.org>
Message-Id: <20060508202015.A2C734F1D3@homer.w3.org>


> > Then you can say "everything which starts with http://www.w3.org/ is
> > child-safe" like:
> > 
> >     if 
> >        x.uri.startsWith("http://www.w3.org/")
> >     then
> >        icra:ChildSafe(x)
> > 
> > I expect the RIF Working Group (for which I am the W3C staff contact) to
> > provide something that will work for points #2 and #3.  I'm not sure the
> > URI property is going to come from.

I should also say that an application specific approach like:

    <http://www.w3.org/> rdf:type icra:ChildSafeSiteTree.

seems fine, and in the presense of suitable rules could generate
 
    <...> rdf:type irca:ChildSafe.

as necessary.    The rule might be:

      if
         icra:ChildSafeSiteTree(y)
         y.uri = prefix
         x.uri.startsWith(prefix)
      then
         icra:ChildSafe(x)


> I'm very glad to see this conversation happening. I've always seen
> RDF-CL as a stepping stone for PICS-like apps, with RIF being the
> ultimate way of expressing the kinds of generalisations we want here.
> I'm looking forward to test-driving RIF's language on these apps...
> 
> Re the URI property, perhaps this can be done in the XG. There might be 
> a bit of care needed around canonicalisation, charset, considerations, 
> also whether we use plain literals or datatyped, and if former, whether
> we consider xml:lang relevant for identity reasoning. In other words,
> we'd need a test suite.

Here's one proposal, by the way, although it was made before RDF had
language tags or datatype literals:

   http://www.w3.org/2001/12/uname/#uname

> For the string functions, SPARQL seems to have some useful bits:
> 
> http://www.w3.org/TR/2006/WD-rdf-sparql-query-20060220/#SparqlOps

I don't see anything like startsWith.  Am I missing it?

> Will some of these also be exposed in the RIF language?

Sorry, I'm not sure what SPARQL has.   If it's suitable, I suspect RIF
will adopt it.

      -- Sandro
Received on Monday, 8 May 2006 20:20:26 UTC

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