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Re: Notes on updates to RDF Schema

From: pat hayes <phayes@ai.uwf.edu>
Date: Wed, 30 Oct 2002 11:24:21 -0600
Message-Id: <p05111b1bb9e5ba705607@[65.217.30.130]>
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org

>I've prepared the attached as some briefing notes to help Danbri do 
>the update to schema.  Please feel free to correct bits that you 
>think are wrong or add bits that are missing.
>
>Datatypes
>=========
>
>o Define rdfs:Datatype the class of all datatypes.
>o rdfs:Datatype is a subclass of rdfs:Class, i.e. datatypes are classes
>o The class extension of a datatype class is the value space of the class.
>o a range constraint on a property can take a datatype as its value
>o rdfs:XMLLiteral is a member of rdfs:Datatype
>o rdfs:XMLLiteral is a subClass of rdf:Literal

There is a possible snag here. 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. 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. Or else I could just wrote 
rdf:Literal out of the model theory and declare it semantically 
underdetermined, like rdf:comment.

Pat

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Received on Wednesday, 30 October 2002 12:24:54 EST

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