W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

RE: Answer to the question: What is a "value" to RDF

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 14 Nov 2001 20:46:51 -0600
Message-Id: <p05101060b818dbba4ade@[65.212.118.147]>
To: Patrick.Stickler@nokia.com
Cc: w3c-rdfcore-wg@w3.org
>  > >....
>>  >>  >This means that, whether a given RDF class denotes both
>>  >>  >a value space and a lexical space, or only a value space, any
>>  >>  >inferences about the valid membership of a given typed value in
>>  >>  >a superordinate class has only to do with value space.
>>  >>
>>  >>  No. If a class *denotes* a lexical space, then membership in that
>>  >>  lexical space will be relevant, obviously.
>>  >
>>  >Relevant when parsing the lexical form and mapping it to a value,
>>  >yes, but not necessarily relevant to operations taking
>>  >subClassOf relations into account.
>>
>>  No, really. If a class name denotes a class consisting of lexical
>>  forms, i.e. if lexical forms are in the class extension, then lexical
>>  forms are what determine class membership and subClassOf relations.
>>  It would be the same if you substituted 'chickens' for 'lexical
>>  forms'.
>
>I think we're speaking different languages again... (maybe)

Yes, forget it. I think I was focussing in on 'denotes' too closely, is all.
...

>Right. (Hey! We're beginning to sync... ;-)

Incredible.

>  > >>  Now, the question arises, is
>>  >>  that semantic value a string or (say) a number?
>>  >
>>  >But the question is irrelevant within the scope of RDF! The
>>  >representation of the semantic value is undefined.
>>
>>  I am not asking about a representation, but about the value itself,
>>  the denotation of the representation: what kind of thing does the
>>  literal mean/refer to/denote.
>>
>>  The question is not irrelevant; it is central to the model theory.
>>  This entire debate has to eventually get cashed out in a model theory
>>  for this language.
>
>Do you mean, does the literal represent a value or a string
>that represents the value?

Right.

>I'd say that it represents the value, within the context of
>a data type.

Right, I agree that makes sense; but the S/DC proposals don't take 
that route; they have all literals in the graph just denoting the 
string that represents the value, and then have a bNode to denote the 
value. It seems kind of arse-backwards, but I have to admit it sure 
makes the semantics of literals simpler if they all just represent 
strings, period.

Pat
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Received on Wednesday, 14 November 2001 21:46:49 EST

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