W3C home > Mailing lists > Public > semantic-web@w3.org > November 2008

RE: DBpedia 3.2 release, including DBpedia Ontology and RDF links to Freebase

From: John Goodwin <John.Goodwin@ordnancesurvey.co.uk>
Date: Tue, 18 Nov 2008 09:09:31 -0000
Message-ID: <6788A63BA7EC0543BDC998EA0C758568026E95AD@EMAIL.ordsvy.gov.uk>
To: "Jens Lehmann" <lehmann@informatik.uni-leipzig.de>, <semantic-web@w3.org>
Cc: <dbpedia-discussion@lists.sourceforge.net>, <semantic-web@w3.org>, <public-lod@w3.org>


> Regarding you arguments:
> 
> Too tight restrictions: Which ones specifically are too 
> tight? If the restrictions cause inconsistencies (which they 
> are likely to do at the moment), then this is a signal a 
> problem in the DBpedia data. (Which is one of the purposes of 
> imposing restrictions.)

I've noticed that properties like "father" have a domain of "British
Royal or Monarch" and I wonder if this is too tight. Would you not save
yourself headaches in the future by relaxing that restriction to Person?
For example if you want to add in "father" information for US presidents
will you then have to go back and edit your OWL ontology to include US
presidents in the domain of "father". 

Furthermore, I understand disjunctions can be expensive when reasoning
(not sure if that would be the case in the Dbpedia ontology as it
doesn't use that much extra OWL). 


> I think there are many of those. First of all, they allow 
> checking consistency in the DBpedia data. Having consistent 
> data allows to provide nice user interfaces for DBpedia. 

I'm still not sure how domain and range will help check consistency.
Don't you need OWL disjoints and other information to find
inconsistencies, unless of course you check all the inferred types for
the instances? 

> As a consequence, OWL should never be used for consistency checking?

You can use it for checking satifiability of classes and consistency of
ontologies if you add enough information, but otherwise ontologies will
generally just add more information that lead to extra entailments.

John
.


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Received on Tuesday, 18 November 2008 09:19:02 UTC

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