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Re: RDF datatyping goals (action from teleconference)

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Wed, 16 Jan 2002 09:15:22 +0200
To: Patrick Stickler <Patrick.Stickler@nokia.com>, ext Graham Klyne <Graham.Klyne@MIMEsweeper.com>
CC: Jeremy Carroll <jjc@hplb.hpl.hp.com>, RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <B86AF52A.BAB5%patrick.stickler@nokia.com>

Should we include a discussion of the semantics of rdfs:range,
rdf:value and rdf:type with regards to datatyping of literals
in the "Foundational" datatyping document (sections 1-3 of
Sergey's document)?

Patrick

On 2002-01-15 17:32, "Stickler Patrick (NRC/Tampere)"
<Patrick.Stickler@nokia.com> wrote:

> On 2002-01-15 17:02, "Patrick Stickler" <patrick.stickler@nokia.com>
> wrote:
> 
>> On 2002-01-15 14:38, "ext Graham Klyne" <Graham.Klyne@MIMEsweeper.com>
> wrote:
>> 
>>> At 09:45 AM 1/15/02 +0200, Patrick Stickler wrote:
>>> 
>>>> The semantics of the rdfs:range 'constraint' (as I see it) is to
>>>> define an implicit union of data types, the members being the
> objects
>>>> of the rdfs:range, which may be used to
>>> 
>>> "intersection", not "union" (per WG resolution).
>> 
>> ??? I understood that 'union' meant the intersection of
>> lexical and value spaces.
>> 
>> What's the difference?
> 
> Ahhh, OK, I think I see where your coming from.
> 
> A Union Datatype expects that its members are a member of
> at least one, but not all, of its subtypes.
> 
> But the rdfs:range constraint defines an intersection of types
> (not union) such that a lexical form (property value) is
> considered (or required) to be a member of every specified
> type -- and of course, any of those types can be a Union
> Datatype.
> 
> Thus, I can define a Union Datatype 'myUnion' with xsd:date and
> xsd:duration, which have totally disjunct lexical spaces, and I can
> then say
> 
> ex:someProp rdfs:range xsd:string .
> ex:someProp rdfs:range #myUnion .
> 
> which will never result in a contradition since xsd:string subsumes
> the lexical space of all lexical datatypes.
> 
> Yet if I say
> 
> ex:someProp rdfs:range xsd:date .
> ex:someProp rdfs:range xsd:duration .
> 
> then I am sure to get a contradition every time, regardless of
> whether the literal is a valid xsd:date or xsd:duration since
> all rdfs:range defined types are inferred/required.
> 
> Right?
> 
> If so, then I'm OK with your definition of the equality of (a), (b),
> and (c) with regards to interpretation.
> 
> Patrick
> 
> --
>              
> Patrick Stickler              Phone: +358 50 483 9453
> Senior Research Scientist     Fax:   +358 7180 35409
> Nokia Research Center         Email: patrick.stickler@nokia.com
> 
> 

--
               
Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Wednesday, 16 January 2002 02:14:37 EST

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