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Issue #qu-02 rdfs:member functional?

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Thu, 20 Feb 2003 12:58:39 +0000
Message-Id: <5.1.0.14.0.20030220125710.02fcf340@localhost>
To: "Qu Yuzhong" <yzqu@seu.edu.cn>, "pat hayes" <phayes@ai.uwf.edu>
Cc: "rdf-comments" <www-rdf-comments@w3.org>

At 19:32 19/02/2003 +0800, Qu Yuzhong wrote:


> > At 11:25 18/02/2003 -0600, pat hayes wrote:
> >
> > [...]
> >
> > >>2. About rdf:_nnn  (section 3.2.2 of the RDF Semantics spec)
> > >>
> > >>Please consider adding one more example to clarify the meaning of
> > >>rdf:_nnn, such as the following:
> > >>
> > >>_:xxx rdf:type rdf:Seq.
> > >>_:xxx rdf:_2 <ex:a> .
> > >>_:xxx rdf:_2 <ex:c> .
> > >>
> > >><ex:a> and <ex:c> should denote the same thing? In other words, the
> > >>property rdf:_nnn should be a functional property? (I haven't found any
> > >>explanation about this issue in the spec)
> > >
> > >Since RDFS has no notion of equality, there is no way to express the idea
> > >of a functional property in RDFS. Whether or not a property is functional
> > >can make no difference to any RDFS entailment. In semantic extensions 
> like
> > >OWL which can express the idea of a functional property, it would
> > >certainly be natural to impose this requirement; but then that must be
> > >part of the spec of the extended language.
> >
> > Qu,
> >
> > Does Pat's explanation of the absence of this entailment resolve your
> > issue, or would you like the WG to consider this as a formal last call 
> comment?
>
>Yes, RDFS has no explicit notion of equality and functional property. But 
>we can specify rdf:_nnn to be a functional property by an extra semantic 
>condition for rdf-interpretation (refer section 3.1). For example, add an 
>extra semantic condition as follows:
>
>If <x,y1> and <x,y2> are in IEXT(I(rdf:_nnn)) then y1 equals y2 in IR.
>
>(This also reveals the powerfulness, maybe ambitious, of the semantic 
>framework in the spec.)
>
>Pat's response partially resolves my issue. Hope the WG could consider 
>this as a formal last call comment.

Qu,

I have recorded this as a formal comment at:

   http://www.w3.org/2001/sw/RDFCore/20030123-issues/#qu-02

The WG will consider this and respond in due course.

Thanks for your time and effort commenting on our WD's.

Brian
Received on Thursday, 20 February 2003 07:57:58 GMT

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