Re: Managing Co-reference (Was: A Semantic Elephant?)

On 15 May 2008, at 13:17, Aldo Gangemi wrote:
>>> or a city as from Cyc to a wikipedia article of that city (as done  
>>> in DBpedia).
>>
>> DBpedia doesn't contain any owl:sameAs statements between Cyc  
>> resources and Wikipedia articles.
>
> See the extended datasets (http://wiki.dbpedia.org/Downloads) for  
> "Links to Cyc" at:
> http://downloads.dbpedia.org/preview.php?file=3.0_sl_en_sl_links_cyc_en.nt.bz2

These are links from Cyc to DBpedia resources. DBpedia resources are  
*not* Wikipedia articles.

http://en.wikipedia.org/wiki/Berlin identifies a Wikipedia article, a  
web page, about a city.

http://dbpedia.org/resource/Berlin identifies a city, not an article  
or web page.

http://en.wikipedia.org/wiki/Berlin is thus a page whose topic is http://dbpedia.org/resource/Berlin 
  .

An article about a city is of course not the same as a city. This  
difference is explicitly modelled in DBpedia.

>> [snip]
>>> It is reasonable, as Richard Cyganiak wrote at the time, that we  
>>> have to work around the quirks [2], nonetheless, if there is no  
>>> real need, why should we work around the quirks caused by a  
>>> pointless identity assumption?
>>
>> I feel misquoted. In the original discussion [1], I encouraged the  
>> use of owl:sameAs between three different definitions (Geonames,  
>> GEMET and DBpedia) of the concept of a “canal”. I did *not*  
>> advocate to gloss over the difference between a thing and a  
>> document about that thing, as you imply by your examples above. To  
>> the contrary, I have insisted on this difference many times, e.g.  
>> in [2].
>
> That's ok. I used an indirect quotation of yours from Bernard  
> Vatant's blog.
> Talking of content, on the sameness of Geonames and DBpedia articles  
> I have anyway a different intuition:
> Geonames refer to geographical locations,

Yes.

> DBpedia entries to articles,

No. DBpedia refers to the *topic* of articles, which are geographical  
locations in some cases. If you look up any DBpedia identifier on the  
Semantic Web, you will find RDF statements to hat effect.

Richard



> which on their turn can refer to geographic locations
>
>> At the end of the day, we have to keep in mind that we are talking  
>> about the Web. Statements will be subjective, inconsistent and  
>> wrong. This also applies to owl:sameAs statements. They are claims,  
>> not facts. Deal with it.
>
> Agreed. I do not want to be picky about that: SW is Web, and errors  
> are life.
> Just there is no need to use owl:sameAs in many cases, and at least  
> in LOD large projects, this can be avoided easily.
>
> Thanks for clarifying
> Aldo
>
>
> _________________________________
>
> Aldo Gangemi
>
> Senior Researcher
> Laboratory for Applied Ontology
> Institute for Cognitive Sciences and Technology
> National Research Council (ISTC-CNR)
> Via Nomentana 56, 00161, Roma, Italy
> Tel: +390644161535
> Fax: +390644161513
> aldo.gangemi@cnr.it
>
> http://www.loa-cnr.it/gangemi.html
>
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>
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>

Received on Friday, 16 May 2008 14:31:51 UTC