W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > October 2002

Re: Notes on updates to RDF Schema

From: pat hayes <phayes@ai.uwf.edu>
Date: Wed, 30 Oct 2002 16:15:55 -0600
Message-Id: <p05111b2eb9e609c2ef47@[65.217.30.130]>
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org

>At 11:24 30/10/2002 -0600, pat hayes wrote:
>
>[...]
>
>>>o rdfs:XMLLiteral is a subClass of rdf:Literal
>>
>>There is a possible snag here.
>
>I thought there might be.
>
>>I think we are (as a group) still somewhat unclear about the 
>>meaning of rdf:Literal. In the MT I was very explicit that that 
>>class contained literal *values*, not literals.
>
>Yup.  Oh bu**er I see what you mean.  Or do I?  There is a value 
>space for rdfs:XMLLiteral, say XMLVAL..  There is the set of things 
>that literals (not the XML variety) denote, say LITVAL.  The  class 
>extension of Literal is XMLVAL union LITVAL.  Does that work?

Sure, I don't mind having XML structures in the literal value space; 
after all, they are a kind of datatype value. My concern is really 
more to do with the issue that came up in a msg from Patrick last 
week, where he seemed (and he is not alone) to be assuming that 
rdf:LIteral  was the class of literals. I hope its not, because now 
that literals have gotten so complicated, they are certainly not 
literal values any more. It used to be strings all the way down, but 
times have changed.

>
>>  I was expecting a backlash, but nobody noticed :-). Now that 
>>datatyped literals can denote non-strings, the difference between 
>>those two interpretations of rdf:Literal is again rather important, 
>>so can I ask the group to decide clearly and firmly which 
>>interpretation they want to have? Note that if rdf:Literal is 
>>supposed to be the class of literals, then all triples of the form
>>
>>aaa rdf:type rdf:Literal .
>>
>>will be false in all interpretations.
>
>I don't follow that one.  We have been careful not to say whether 
>literals are resources or not, but we all know they are really.

Do we? I don't think they are any more. Literal values might or might 
not be, but literals???

Pat

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Received on Wednesday, 30 October 2002 17:16:36 EST

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