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RE: Literals: lexical spaces and value spaces

From: <Patrick.Stickler@nokia.com>
Date: Tue, 13 Nov 2001 00:13:38 +0200
Message-ID: <2BF0AD29BC31FE46B78877321144043162175A@trebe003.NOE.Nokia.com>
To: phayes@ai.uwf.edu
Cc: w3c-rdfcore-wg@w3.org


> -----Original Message-----
> From: ext Patrick.Stickler@nokia.com 
> Sent: 12 November, 2001 22:47
> To: phayes@ai.uwf.edu
> Cc: w3c-rdfcore-wg@w3.org
> Subject: RE: Literals: lexical spaces and value spaces
> 
> 
> 
> > >and one can end up with a literal value having a lexical
> > >form that is not compatible with the data type of the
> > >property.
> > 
> > true, if the datayping information given in somehow incorrect. But 
> > the same can be said for a local type; if you give the 
> wrong datatype 
> > information, things will go wrong. You have such an example 
> above, in 
> > fact.  What has that got to do with the local/nonlocal distinction?
> 
> But if the type is determined by the rdfs:range constraint,
> and the type is different between the original property of
> the statement and some superordinate property that the literal
> is bound to by inference, an error in interpretation can occur,
> as one will be determining the data type by the range defined
> for the superordinate property which may not have a compatible
> lexical space.
> 
> The literal may be unparsable or may be misinterpreted.
> 
> Thus, given the data
> 
>  aaa ex:hexShoeSize "12" .
>  ex:hexShoeSize rdfs:subPropertyOf ex:shoeSize .
>  ex:hexShoeSize rdfs:range foo:hexInteger .
>  foo:hexInteger rdfs:subPropertyOf xsd:integer .



Oops. That should have been

   foo:hexInteger rdfs:subClassOf xsd:integer .



>  ex:shoeSize rdfs:range xsd:integer.
> 
> And a query
> 
>  aaa ex:shoeSize ?x .
> 
> Which is satisfied as
>  -> x = "12"
> 
> Which based on the knowledge
> 
>  ex:shoeSize rdfs:range xsd:integer
> 
> Gets interpreted as
> 
>  int value = parseLiteral(xsd:integer,"12")
> 
>  value = 12
> 
> BOOM!   (should be 18!)
> 
> Eh?   ;-)
> 
> Thus, either literals must be bound to types locally,
> or literals must be inseperable from their original
> predicates.
> 
> Both are satisified if statements are the basis for
> interpretation and query binding.
> 
> > >This, of course, presumes that we are not asserting the
> > >global constraint on data types that the lexical space of
> > >any data type must be a proper subset of the lexical space
> > >of all of its superordinate types.
> > 
> > Ah, but we must make that assumption; I have already conceded 
> > that point.
> 
> But XML Schema simple data types fail that requirement. Thus,
> we cannot make that assumption. Only value spaces for XML
> Schema simple types are proper subsets of the value spaces
> of their superordinate types. Lexical space is specific to
> each type. I had hoped that was not the case, but it is.
> 
> Patrick
> 
Received on Monday, 12 November 2001 17:14:00 EST

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