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Re: email straw poll: literal semantics proposals

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Tue, 08 Oct 2002 18:23:21 +0100
Message-Id: <5.1.0.14.0.20021008181716.02284758@0-mail-1.hpl.hp.com>
To: Frank Manola <fmanola@mitre.org>
Cc: RDF Core <w3c-rdfcore-wg@w3.org>

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
Received on Tuesday, 8 October 2002 13:26:20 EDT

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