Re: stating that something doesn't exist

On May 22, 2008, at 8:39 AM, Johnson, Matthew C. (LNG-HBE) wrote:

> [[MCJ]] I suppose that given the open world assumption, someone else
> would not know this unless there was an explicit mysch:notLinksTo
> assertion or one relied upon the interpretation of a query (that shows
> that mysch:linksTo does not exist between pub 2 and pub 3.  This is  
> what
> I'm coming around to anyway...  Perhaps I'm really struggling with the
> notion of open world assumptions vs. closed.  In SQL (closed world),  
> one
> frequently uses "select count(*) ..." in order to determine whether a
> relationship exists.  In the open web, I can understand that one  
> cannot
> assume that a given graph incorporates absolutely every statement  
> [about
> a given thing] but I wonder whether if it is ok to make such an
> assumption within one's own [possibly local/corporate] domain?  Would
> this be considered an abuse of OWL's and RDF's intent?

I think that one has to make one's own judgements. The intent of the  
open world assumption is to not make a global assumption for  
everybody. Certainly, if within your organization you are comfortable  
that you have adequate information to make decisions, no one is going  
to argue with that.

-Alan