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Re: matching existing existentials in the consequent.

From: Jeff Thompson <jeff@thefirst.org>
Date: Sun, 20 Apr 2008 22:30:57 -0700
Message-ID: <480C2691.60304@thefirst.org>
To: Tim Berners-Lee <timbl@w3.org>
CC: cwm talk <public-cwm-talk@w3.org>

Tim Berners-Lee wrote:
> Jeff,
> 
> Good question.
> 
> Of course
> 
>     bob a :CatLover; :owns :fluffy, [a :Cat].
> 
> does not mean he owns *another* Cat.  It means he owns fluffy, and he 
> owns a cat.
> Those of us who know fluffy is a cat know that the second part of it, 
> {:bob :owns [ a :Cat ]} doesn't give us any new information.

How then would you represent that bob owns two cats?
What if bob owns two cats who just happen to have the name "Fluffy"?  Up
until now I assumed a graph could have:

bob owns [a Cat; name "Fluffy"].
bob owns [a Cat; name "Fluffy"].

and that this would assign two different blank nodes so that bob owns
two separate cats (assuming that "owns" is not an owl:FunctionalProperty).
I have read the references Dan graciously provided about "lean" graphs
but still can't sort out if a lean graph forbids this way of saying
that bob owns two cats named "Fluffy".

- Jeff
Received on Monday, 21 April 2008 05:31:39 GMT

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