W3C home > Mailing lists > Public > www-rdf-interest@w3.org > September 2002

Re: Can a property not have a uriref?

From: Zhang Jeff <jeffzhang726@yahoo.com.cn>
Date: Wed, 18 Sep 2002 10:59:10 +0800 (CST)
Message-ID: <20020918025910.4217.qmail@web20710.mail.yahoo.com>
To: sandro@w3.org
Cc: www-rdf-interest@w3.org

 --- Sandro Hawke <sandro@w3.org> 的正文:> > 
> >  --- Sandro Hawke <sandro@w3.org> 的正文:> 
> > > 
> > > > I had assumed that all predicates must be
> named by
> > > some uriref - this 
> > > > seems obvious where a predicate appears in a
> > > simple s o p triple.
> > > ...
> > > > But today I thought of another possible
> counter
> > > example (where we are 
> > > > dealing with reification) that may actually
> make
> > > sense in some 
> > > > circumstances.
> > > 
> > > Actually, there are lots of times when it makes
> > > sense to have arcs
> > > without URIRef labels, even without reification.
> 
> > > Two that come to
> > > mind are Currying and using properties when you
> only
> > > know their
> > > unambiguous properties.
> > 
> > If you really want it, why not use an instance of
> > "http://www.w3.org/...#Property" which is just
> > a property without any specific meaning?
> > OR introduce an "anonymous property",into RDF
> > vocabulary?
> > OR in application level,such as
> > "http://www.mycompany.com/unknowProp"  typed as
> > rdf:Property ? It is easy to deal it as a "general
> > property" in application level.
> > (I don't have much knowledge of AI or theories of
> > models or math and I just can not see the
> complexity
> > of this problem. Is it really so difficult? )
> > And,is there any similar concepts in logics or
> > relation algebra or other knowledge
> representations?
> 
> You're 99% right.  Skolemizing an RDF graph
> (labeling unlabeled nodes
> and arcs with UUIDS) does not change its meaning as
> an assertion.
> The other 1% comes from not wanting UUIDs cluttering
> up databases, and
> wanting to use RDF with non-assertional attitudes,
> such as to discuss
> what someone else said/signed in RDF.   (I say
> "Something is red."  If
> you put "uuid:wer4353535 is red" into your DB the
> results will generally be
> the same.  But you shouldn't claim I said
> uuid:wer4353535 was red.)
> 

I see.
If we introduce a general resource that standing for 
just "some thing" and a general property for "some 
property" into the vocabulary, somewhat like
wildcards,can the problem be resolved?
So you can say" rdf:something  is red" or 
"myNameSpace:something is red".
There are concepts of indefinite pronouns in natural 
languages and I think it is natural to introduce
similar things into artificial languages like RDF.


>    -- sandro 


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Received on Tuesday, 17 September 2002 22:59:11 GMT

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