W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > July 2001

Re: Proposal: #rdfms-identity-anon-resources

From: pat hayes <phayes@ai.uwf.edu>
Date: Fri, 13 Jul 2001 11:34:02 -0700
Message-Id: <v04210105b774ed19979c@[]>
To: jos.deroo.jd@belgium.agfa.com
Cc: w3c-rdfcore-wg@w3.org
> > > based on what we have testcased at
> > > http://www.agfa.com/w3c/euler/#Problem
> > > I completely agree with you and I really
> > > wonder how else we could model/infer
> > > http://www.agfa.com/w3c/euler/tpoint-result.n3 or
> > > http://www.agfa.com/w3c/euler/tpoint-all.n3
> >
> > The answer is that in RDF, you *can't* infer this stuff.
> >
> > You use N3, which is way more expressive than RDF; it has negation
> > and universal quantifiers, just for a start.
>Fine, but per http://www.w3.org/2000/10/swap/log#
>and e.g. http://www.w3.org/2000/10/swap/model.n3#
>one *can* produce/consume regular N-Triples, no?

Yes and no. They do produce triples, but how are those triples 
interpreted? If they are interpreted using the meanings suggested by 
the M&S (I refrain from saying 'semantics') then you can't validly 
infer this stuff. Cwm infers it by imposing some extra 
interpretations on the triples, ie in effect treating them as 
triple-encodings of expressions in some other language, which as far 
as I know has never been precisely defined anywhere, though it seems 
to be something close to prolog with a nonstandard negation (? A 
guess, as the only way to know for sure is to inspect the Cwm code 
and reverse-engineer the intended semantics.).

  http://www.w3.org/2000/10/swap/log# pretty much says this directly, eg:
log:N3Document a rdfs:Class;
         rdfs:comment    """A document which, which parsed as Notation3
as defined in general by http://www.w3.org/DesignIssues/Notation3.html
and this schema, conveys the intent of the author by the semantics defined
on those specifications, and the semantics defined by the specifications
of any identifiers used in the document.
""" .
log:implies a rdfs:Property;
     rdfs:comment "Logical implication. Understood natively by cwm.";
     rdfs:range log:Formula;
     rdfs:range log:Formula.

log:resolvesTo a rdf:Property;
     rdfs:domain doc:Work;
     rdfs:range  log:Formula;
     rdfs:label  "forumla";
     rdfs:comment """This connects a document and the formula it parses to.
         Cwm knows how to go get a document and parse it in order to 
evaluate this.""".
Notice in the last two cases the explicit reference to Cwm's 'native' 
ability to interpret something that is not defined in  RDF.

Pat Hayes

(650)859 6569 w
(650)494 3973 h (until September)
Received on Friday, 13 July 2001 14:34:04 UTC

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