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Re: Should rdf:value have a semantics?? (was: Re: Quick review of RDFprimer)

From: Frank Manola <fmanola@mitre.org>
Date: Tue, 03 Dec 2002 16:07:44 -0500
Message-ID: <3DED1D20.2E92BB97@mitre.org>
To: pat hayes <phayes@ai.uwf.edu>
CC: w3c-rdfcore-wg@w3.org

pat hayes wrote:
> 
> >More discussion below:
> >
> 
> snip
> 
> >  >
> >>  So more generally, to the WG: should I give rdf:value a model theory?
> >>  Speak soon, guys. Unless I hear otherwise I will do this:
> >>
> >>  aaa rdf:value "bbb" .
> >>
> >>  means that there is some conventional mapping M from lexical forms
> >>  under which I(aaa) = M(bbb). Doesn't say much, but it might be
> >>  useful, particularly if we say that any datatype L2V mapping counts
> >>  as a 'conventional mapping'.
> >
> >I'm not clear on something.  This doesn't preclude the value of an
> >rdf:value property from being a typed literal does it?
> 
> Well, yes, it would, but isn't that appropriate? I guess it might
> make sense to say
> 
> aaa rdf:value "10"^^xsd:string .
> 
> but one might as well omit the type in this case; and it would never
> make sense to say
> 
>   aaa rdf:value "10"^^xsd:integer .
> 
> since integers aren't lexical forms.
> (If this does make sense, what is it supposed to mean?)
> 

Pat--

Back up a minute.  The "historic" use of rdf:value was for the cases
like

my:cat rdf:type ex:DomesticCat .
my:cat ex:weight _:x .
_:x rdf:value "15" .
_:x ex:unit ex:Kilogram

Now that we have datatypes, the extension of this usage to 

my:cat rdf:type ex:DomesticCat .
my:cat ex:weight _:x .
_:x rdf:value "15"^^xsd:integer .
_:x ex:unit ex:Kilogram

seems perfectly straightforward.  You're being more precise about what
the value is (it's a number, rather than a string), and you need other
properties anyway to specify the units (and anything else).  I'm not
such a fan of rdf:value, but it seems to me that restricting rdf:value
to preclude this usage might seem somewhat artificial to those already
using it.

--Frank

-- 
Frank Manola                   The MITRE Corporation
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Received on Tuesday, 3 December 2002 16:07:47 EST

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