Re: Covering Axiom Question

True, but there's more to the story . . . 

2009/10/2 Toby Inkster <tai@g5n.co.uk> 
>         If I define:
>         
>                :Primate owl:equivalentClass [
>                        owl:unionOf (:Human :Monkey)
>                        ] .
>                :Human owl:disjointFrom :Monkey .
>         
>         (And I realise I'm vastly oversimplifying the biology here!)
>         then a
>         statement like this:
>         
>                :Bob rdf:type :Primate .
>         
>         is not inconsistent. In the first snippet, you've asserted
>         that all
>         primates must be human or monkey, and cannot be both. In the
>         second, you've asserted that Bob is a primate. Therefore, Bob
>         must be human or a monkey, but not both.
>         
>         But because of the open world assumption, that's OK. Bob *is*
>         either a human or a monkey, and not both - but we haven't said
>         which he is. 
> 
Correct.  But according to RDF semantics
http://www.w3.org/TR/rdf-mt/#sinterp
in one interpretation of the above RDF statements Bob may be a human,
while in another interpretation Bob may be a monkey.  But the RDF
semantics doesn't tell us which interpretation to pick -- that's up to
the application.

In other words, in application1, the above RDF data may be combined with
other RDF data (call it r1) that constrains Bob to be a human, while in
application2 the above RDF data may be combined with different RDF data
(call it r2) that constrains Bob to be a monkey.  This does not mean
that either application is wrong.  It just means that the above RDF data
cannot be used with both r1 and r2 *in the same application*.  

This paper, from last July's International Joint Conference on
Artificial Intelligence, discusses this further and explains how a "URI
declaration" constrains the possible interpretations corresponding to a
URI:
http://dbooth.org/2009/denotation/



-- 
David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.

Received on Friday, 2 October 2009 18:39:23 UTC