W3C home > Mailing lists > Public > public-semweb-lifesci@w3.org > March 2013

Re: owl:sameAs - Is it used in a right way?

From: David Booth <david@dbooth.org>
Date: Sat, 16 Mar 2013 00:35:20 -0400
Message-ID: <5143F688.2050607@dbooth.org>
To: Jeremy J Carroll <jjc@syapse.com>
CC: Umutcan ŞİMŞEK <s.umutcan@gmail.com>, Kingsley Idehen <kidehen@openlinksw.com>, public-semweb-lifesci@w3.org
Hi Umutcan,

You have indeed stumbled on a deep question, and I think Jeremy's 
suggestion is exactly right.  This paper on "Resource Identity and 
Semantic Extensions:
Making Sense of Ambiguity" illustrates how owl:sameAs works in RDF 
semantics:
http://dbooth.org/2010/ambiguity/paper.html#sameAs

There are two keys to understanding owl:sameAs.  One is to answer the 
question: what RDF graph are you considering?  The other is to 
understand that the same URI may denote different things in different 
RDF graphs.  It is only when RDF statements are in the *same* graph that 
the RDF semantics requires the URI to denote the same resource.  That is 
why the question of what graph you are considering is crucial, and why 
Jeremy suggested keeping the different perspectives in different graphs.

FYI, the above paper also explains how you can "split" the identity of 
an RDF resource if you need to merge RDF graphs that use the same URI in 
contradictory ways.

David


On 03/15/2013 02:29 PM, Jeremy J Carroll wrote:
> I did not find this a rookie question at all.
>
> This seems to get to the heart of some of the real difficult issues in Semantic Web.
>
> My perspective is different from yours, and a resource description that I author is a description of the resource from my perspective; a resource description that you author is a description from your perspective.
>
> If I have some detailed application that depends in some subtle way on my description, I may want to ignore your version; on the other hand, a third party might want to use both of our points of view.
>
> One way of tacking this problem is to have three graphs for this case:
>
> Gj, Gu, G=
>
> Gj contains triples describing my point of view
> Gu contains triples describing your point of view
> G= contains the owl:sameAs triples
>
> Then, in some application contexts, we use Gj, sometimes Gu, and sometimes all three.
>
> Jeremy
>
>
>
>
> On Mar 15, 2013, at 11:02 AM, Umutcan ŞİMŞEK <s.umutcan@gmail.com> wrote:
>
>> Thanks for the quick answer : )
>>
>> So this issue is that subjective for contexts which allows to use owl:sameAs to link resources  if they are not semantically even a little bit related in real world?
>>
>> Sorry if I'm asking too basic questions. I'm still a rookie at this :D
>>
>> Umutcan
>>
>>
>> On 15-03-2013 19:38, Kingsley Idehen wrote:
>>> On 3/15/13 1:05 PM, Umutcan ŞİMŞEK wrote:
>>>> My question is, does LODD use owl:sameAs properly? For instance, are those two resources, dbpedia:Metamizole and drugbank:DB04817 (code for Metamizole), really identical? Or am I getting the word "property" in the paper wrong?
>>> The question is always about: do those URIs denote the same thing? Put differently, do the two URIs have a common referent?
>>>
>>> ## Turtle ##
>>>
>>> <#i> owl:sameAs <#you>.
>>>
>>> ## End ##
>>>
>>> That's a relation in the form of a 3-tuple based statement that carries entailment consequences for a reasoner that understand the relation semantics. Through some "context lenses" the statement above could be accurate, in others totally inaccurate.
>>>
>>> Conclusion, beauty lies eternally in the eyes of the beholder :-)
>>>
>>
>>
>
>
>
>
>
Received on Saturday, 16 March 2013 04:35:48 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 14:53:01 UTC