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RE: datatypes and MT

From: <Patrick.Stickler@nokia.com>
Date: Tue, 6 Nov 2001 11:58:56 +0200
Message-ID: <2BF0AD29BC31FE46B7887732114404316216D3@trebe003.NOE.Nokia.com>
To: melnik@db.stanford.edu
Cc: w3c-rdfcore-wg@w3.org


> -----Original Message-----
> From: ext Sergey Melnik [mailto:melnik@db.stanford.edu]
> Sent: 06 November, 2001 00:33
> To: Stickler Patrick (NRC/Tampere)
> Cc: w3c-rdfcore-wg@w3.org
> Subject: Re: datatypes and MT
> 
> 
> Patrick.Stickler@nokia.com wrote:
> > 
> > >       <rdf:Description rdf:about="#me">
> > >         <shoeSize>
> > >            <integer decimalRep="10"/>
> > >         </shoeSize>
> > >     </rdf:Description>
> > 
> > The problem with this representation is that if we add
> > additional qualification to the literal value, e.g.
> > 
> >     <integer decimalRep="10" foo:bar="xyz"/>
> > 
> > then an application that does not understand the specific
> > semantics of any vocabulary other than RDF and RDFS (such
> > as a generic tool) does not know which is the actual
> > value of the property 'shoeSize'... "10" or "xyz" since
> > insofar as the graph representation is concerned, they
> > are equally opaque.
> > 
> > IMO, regardless of the final mechanisms employed and the
> > level of typing or qualification of literals, it should
> > *always* be possible for a generic application to
> > differentiate on the basis of the graph itself, which
> > "child" of a property node constitutes the value node
> > and which are simply qualifications of that value.
> > 
> > The above proposal does not, as far as I can see,
> > provide for that reliable distinction.
> 
> As far as I can see it, the reliable distinction you are talking about
> is not always possible. Think of the following case:
> 
> <complex realDecimal="1.0" imaginaryDecimal="2.0"/>
> 
> as in
> 
> _x rdf:type complex
> _x realDecimal "1.0"
> _x imaginaryDecimal "2.0"
> 
> Above, properties realDecimal and imaginaryDecimal can be 
> thought of as
> "partial mappings" from the lexical space of decimals to the 
> value space
> of complex numbers. Each of the properties restricts the 
> interpretation
> of the complex value. However, the complex value can be pinned down
> unambiguously only using *both* property values. In other words, the
> interpretation of _x is functionally determined by the two property
> values.

Well, just because there might be a few cases that
don't fit a generic modelling, doesn't mean we shouldn't
strive for as much consistency as possible. 

> (As a side remark: of course, I'd prefer a different type of modeling,
> in which the complex number is composed of two real numbers 
> rather than
> gets determined by two lexical tokens.)

Right. Such as <complex>1.0/2.0</complex>, eh?

Cheers,

Patrick
Received on Tuesday, 6 November 2001 04:59:17 EST

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