Re: new model theory for DAML+OIL

From: Peter F. Patel-Schneider (
Date: 10/04/01

From: Pat Hayes <>
Subject: Re: new model theory for DAML+OIL
Date: Thu, 4 Oct 2001 11:32:29 -0500


> >4/ My hope is that the RDF(S) model theory from the RDF Core WG will
> >eventually include datatypes.  If this is not the case then I expect that
> >it will be able to admit the DAML+OIL version of datatypes.
> I would guess the latter is the likeliest outcome, but its only a 
> guess. Certainly I would want to at least achieve this as a minimum, 
> so let us try to keep our work in alignment as far as possible.
> It still seems to me that the slight weakening of the 
> ICEXT(I(rdf:Literal)) condition (to a subset of LV) is all that is 
> needed to keep the required compatibility, since my LV can be the 
> union of the ranges of your various literal mappings, and it may 
> overlap with IR (and if it does, then your two cases for rdfs:range 
> are both covered by my equation on the intersection.) If you 
> disagree, can you pinpoint the problem, so I can fix it?

I don't think that this works, because mentioning a literal can make it
also be a resource.  Consider

   rdfs:label rdfs:range rdfs:Literal .

   rdfs:range rdfs:label "Range" .

   makes I("Range") in ICEXT(I(rdfs:Literal)
   so <I("Range"), I(rdfs:Literal)> in IEXT(I(rdf:type))
   and thus I("Range") in IR

However, there is also a more-basic problem with literals.

Literals have a unique mapping into literal values, which means the
denotation of both literals below have to be the same.

   <Person rdf:ID="John">

This would not allow one to consistently say

   <age rdfs:range xsd:integer>
   <streetAddress rdfs:range xsd:string>


> Pat


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