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

From: Oliver Ruebenacker <curoli@gmail.com>
Date: Thu, 28 Mar 2013 13:17:29 -0400
Message-ID: <CAA=X4ODoGoz9uyU0dCRRhJXK9JXA8cNzMvP1vy8C7WJqC2RB7w@mail.gmail.com>
To: David Booth <david@dbooth.org>
Cc: public-semweb-lifesci@w3.org
     Hello David,

On Thu, Mar 28, 2013 at 8:51 AM, David Booth <david@dbooth.org> wrote:
> On 03/27/2013 11:02 AM, Oliver Ruebenacker wrote:
>>
>>       Hello David,
>>
>>    So if I understand your view correctly, then it could be expressed
>> in a language close to yours as:
>>
>>    "Some people believe that if a URI occurs twice within a graph or
>> statement, it refers to the same thing. But this is a myth! RDF never
>> guarantees that two occurrences of the same URI mean the same thing."
>
>
> No, that's not correct.  If you are talking about what the URI means
> **within that graph**, then:
>
>   - For any interpretation, every occurrence of that URI in that graph
> refers to the same thing; BUT . . .
>
>   - Different interpretations can be applied to that graph, such that the
> URI means one thing in one interpretation, but means something different in
> another interpretation.

  Everything you say relies on one assumption: that interpretations
apply to graphs. You still have not explained what makes you believe
this is always true. In fact, I thought you just conceded in your
previous message that it is not always true.

  Let's say I have a graph G1 containing two statements s1 and s2.
Both s1 and s2 contain the same uri u1. Do you think the RDF specs
allow me to use interpretation I1 for s1 and interpretation I2 for s2?
Could it then be true that u1 in s1 refers to a different thing than
u1 in s2? Even though both occurrences are in G1?

  I'm not interested in whether this is a useful approach, or whether
you would do it this way. I just want to know whether you think the
specs allow this.

> It all comes down to the fact that, in essence, the RDF Semantics spec
> defines a function -- call it RS -- of *two* arguments: one interpretation
> and one graph

  I'm still waiting to hear why one argument needs to be a graph.

> (or a piece of a graph, but that's an unimportant detail).

  No, I don't think that is an unimportant detail. I think that is a
crucial test whether such a view is coherent at all.

     Take care
     Oliver

-- 
IT Project Lead at PanGenX (http://www.pangenx.com)
The purpose is always improvement
Received on Thursday, 28 March 2013 17:17:58 UTC

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