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stating that something doesn't exist

From: Johnson, Matthew C. (LNG-HBE) <Matthew.C.Johnson@lexisnexis.com>
Date: Wed, 21 May 2008 17:10:29 -0400
Message-ID: <0FE5E87C5F0AE84B8C667FDC5224F6DA0229EFA2@LNGDAYEXCP01VC.legal.regn.net>
To: <semantic-web@w3.org>


I'm slowing soaking in what OWL can and cannot do and after reading the
"Lessons For Ontology Writers" post [1] by Ian Davis, I thought I'd go
ahead and ask this capabilities question here.


In OWL, can you directly define a property that says that something does
not occur.  My current use-case is in determining hyper-linking
relationships between various publications.  The following:


mysch:Pub a rdfs:Class .

mysch:linksTo a rdf:Property .


mypubs:p1 a mysch:Pub .

mypubs:p2 a mysch:Pub .

mypubs:p3 a mysch:Pub .


mypubs:p1 mysch:linksTo mypubs:2 .

mypubs:p3 mysch:linksTo mypubs:2 .


Lets me say that pub 1 links to pub 2 and that pub 3 links to pub 2.
However, if I understand the open-world assumption, I cannot assume that
pub 2 does not link to pub 3.  I would need to define something like:


mysch:notLinksTo a rdf:Property .


to explicitly state this fact that pub 2 does not link to pub 3.


My question is whether it is possible in OWL to define a property whose
range of acceptable instances is the list of instances that do not exist
as an object in a mysch:linksTo statement (for a given publication)?
While statically stating that pub 2 does not link to pub 3 is
technically possible for me, it seems unfortunate.  This is because when
a new pub comes along (e.g. mysch:p4), I then have to update all the
statements I've already made.  This is the part that Ian Davis agreed
would cause an explosion of triples.  I would really like to only state
the things that I can programmatically find by parsing the raw syntax of
a publication (e.g. I can find a <a href...> element which provides the
mysch:linksTo assertion) and  would rather the system infer that the
lack of a <mysch:linksTo> relationship really means a


Perhaps the answer is really through SPARQL.  I hope I've made my
question(s) clear.  Please let me know if I haven't.


Thanks for the advice!






Received on Wednesday, 21 May 2008 21:11:18 UTC

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