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Re: email straw poll: literal semantics proposals

From: Frank Manola <fmanola@mitre.org>
Date: Tue, 08 Oct 2002 14:09:58 -0400
Message-ID: <3DA31F76.11367872@mitre.org>
To: Brian McBride <bwm@hplb.hpl.hp.com>
CC: RDF Core <w3c-rdfcore-wg@w3.org>

Brian--

Thanks.  That helps.  

--Frank

Brian McBride wrote:
> 
> At 10:13 08/10/2002 -0400, Frank Manola wrote:
> 
> [...]
> 
> >Comments:
> >
> >1.  As the options are presented, it seems to me we're mixing (a) what the
> >semantics of otherwise undatatyped literals are, and (b) how to  get
> >datatypes attached to otherwise undatatyped literals.  It seems to me that
> >whatever scheme(s) we provide to do (b), we can't necessarily guarantee
> >people will use it/them, so we still have to have a clear answer to
> >(a).  (I think this means we need to intended entailments for the various
> >proposals, as well as the proposed syntax).
> 
> Thinking more about this, my previous response may have been
> inadequate.  The comments about what the literal denotes were meant to be a
> short hand to imply the entailments.  However, in more detail:
> 
> [...]
> 
> >>Proposal B:
> >>   <rdf:Description rdf:about="Jenny">
> >>     <foo:age>10</foo:age>
> >>   </rdf:Description>
> >>   <rdf:Description rdf:about="&foo;age>
> >>     <rdfs:format rdf:resource="&xsd;integer"/>
> >>   </rdf:Description>
> >>The object of an age property denotes a string literal [*] from the
> >>lexical space of xsd:integer.
> 
> The tidy entailment holds.
> 
> >>Proposal C:
> >>   <rdf:Description rdf:about="Jenny">
> >>     <foo:age rdf:datatype="&xsd;integer>10</foo:age>
> >>   </rdf:Description>
> >>   <rdf:Description rdf:about="Film">
> >>     <foo:title>10</foo:title>
> >>   </rdf:Description>
> >>
> >>The object of the age property denotes a member of the value space of
> >>xsd:integer.  The object of the title property denotes a string literal[*].
> 
> The tidy entailment holds, and:
> 
>    <a> <b> "10" .
>    <c> <d> xsd:integer"10" .
> 
> does not entail:
> 
>    <a> <b> _:l .
>    <c> <d> _:l .
> 
> >>Proposal D:
> >>   <rdf:datatype rdf:property="&foo:age" rdf:datatype="&xsd;decimal"/>
> >>   <rdf:Description rdf:about="Jenny">
> >>     <foo:age>10</foo:age>
> >>   </rdf:Description>
> >>   <rdf:Description rdf:about="Johnny">
> >>     <foo:age>10</foo:age>
> >>   </rdf:Description>
> >>Proposal D is proposal C with some syntactic sugar (the rdf:datatype
> >>declaration) so that it is not necessary to put an rdf:datatype attribute
> >>on every use of the age property.
> 
> as for C.
> 
> >>Proposal F:
> >>   <rdf:Description rdf:about="Jenny">
> >>     <foo:age>10</foo:age>
> >>   </rdf:Description>
> >>   <rdf:Description rdf:about="&foo;age>
> >>     <rdfs:range rdf:resource="&xsd;decimal"/>
> >>   </rdf:Description>
> >>The object of an age property denotes an integer from the value space of
> >>xsd:decimal.
> 
> The tidy entailment does not hold.
> 
> Does that help?
> 
> Brian

-- 
Frank Manola                   The MITRE Corporation
202 Burlington Road, MS A345   Bedford, MA 01730-1420
mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-8752
Received on Tuesday, 8 October 2002 14:14:03 EDT

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