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Re: httpRange-14: some dimensions of space of positions

From: Harry Halpin <hhalpin@ibiblio.org>
Date: Fri, 29 Apr 2005 14:42:34 -0400 (EDT)
To: Dan Connolly <connolly@w3.org>
Cc: www-tag <www-tag@w3.org>
Message-ID: <Pine.LNX.4.61.0504291437420.19117@tribal.metalab.unc.edu>

I agree with your point, Dan. OWL can disambiguate assuming that people
are using a vocabulary that has as disjoint sets the two classes (say 
agents and documents) that need to be disambiguated and *crucially* that
vocabulary is known.

I think the problem arises when you don't have that knowledge in your 
RDF graph, and someone just starts making statements about URIs in RDF 
anyways. Then  without the distinction between (for example) agent and 
document being made explicit, the machines does not know the difference.

So, you can make it explicit on the URI level (tdb:, wpn:, etc.) or
make it explicit on the representation (so, when I'm not sure if
the RDF statements are about the document or the agent, I simply  HTTP 
GET  http://www.example.org/PatHayes and I get some nice FOAF statements 
that say this page is a document!).


On Fri, 29 Apr 2005, Dan Connolly wrote:

> On Fri, 2005-04-29 at 10:53 -0400, Harry Halpin wrote:
>> Clarifying the space of possible positions is *always* useful.
>> On Thu, 28 Apr 2005, Dan Connolly wrote:
> [...]
>>> I think OWL is a standardized (and good) far-context mechanism.
>>> far in the sense of possibly-far, i.e. arbitrarily-near-or-far...
>>> it may be nearby or widely known/cached.
>>  	OWL is good, but still misses the point sometimes. If you just
>> make a new OWL statement that says
>> http://www.example.org/PatHayes ex:Denotes "Pat Hayes"
>> doesn't really work, cause sometimes Pat Hayes is Patrick Hayes,
>> and "Pat Hayes" sure looks like an arbitrary string to me :)
> What I'm suggesting is that you can coin terms for
> the class "person" (or "agent") and the class "document",
> say that they're disjoint, and say that something
> is in one of them (and hence not the other), hence
> disambiguating between a person an their homepage.
> I can write this to say that I mean for
> http://www.example.org/PatHayes to denote his homepage:
>  foaf:homepage a owl:InverseFunctionalProperty;
>    rdfs:domain foaf:Agent;
>    foaf:range foaf:Document.
>  foaf:Agent owl:disjointFrom foaf:Document.
>  _:somebody foaf:homepage <http://www.example.org/PatHayes>.
> And if somebody else writes
>  adams:HoopyFrood rdfs:subClassOf foaf:Agent.
>  <http://www.example.org/PatHayes> a adams:HoopyFrood.
> then the machine can compute that we disagree.
> That's the sense in which I think OWL is a (good) far-context
> mechanism for disambiguation.
> p.s. the examples above are written in N3, about
> which see http://www.w3.org/2000/10/swap/Primer
> I also assume http://esw.w3.org/topic/TheUsualPrefixes .
>> http://www.example.org/PatHayes ex:Denotes
>> http://www.example2.org/PatrickHayes
>> doesn't really work, since it just moves the problem to another
>> potentially ambiguous URI.
>> http://www.example.org/PatHayes ex:Denotes
>> http://www.example.org/PatHayes
>> where the second use of the URI means "the non-information resource this
>> web-page is about" seems to break the idea of a URI being a global
>> identity. It's using one URI for two different things, breaking RDF graph
>> merging etc.


 	Harry Halpin
 	Informatics, University of Edinburgh
Received on Friday, 29 April 2005 18:42:39 UTC

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