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

From: Jim McCusker <mccusj@rpi.edu>
Date: Sat, 16 Mar 2013 01:08:28 -0400
Message-ID: <CAAtgn=RaRanFx+P=NTqLf0HEBLfeyz4q5kyLDYbTeGdEGoMTtw@mail.gmail.com>
To: David Booth <david@dbooth.org>
Cc: Jeremy J Carroll <jjc@syapse.com>, Umutcan ŞİMŞEK <s.umutcan@gmail.com>, Kingsley Idehen <kidehen@openlinksw.com>, w3c semweb HCLS <public-semweb-lifesci@w3.org>
David,

The problem with this is that by definition, URIs ALWAYS denote the same
resource. If there is doubt that you might be denoting something other than
what a resource is, you should be defining your own resource.

Jim


On Sat, Mar 16, 2013 at 12:35 AM, David Booth <david@dbooth.org> wrote:

> 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<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 :-)
>>>>
>>>>
>>>
>>>
>>
>>
>>
>>
>>
>


-- 
Jim McCusker
Programmer Analyst
Krauthammer Lab, Pathology Informatics
Yale School of Medicine
james.mccusker@yale.edu | (203) 785-4436
http://krauthammerlab.med.yale.edu

PhD Student
Tetherless World Constellation
Rensselaer Polytechnic Institute
mccusj@cs.rpi.edu
http://tw.rpi.edu
Received on Saturday, 16 March 2013 05:09:12 UTC

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