[Versa] Question about query

[Uche Ogbuji]

On Sun, 2005-09-04 at 13:24 -0400, Chimezie Ogbuji wrote: 
> > What does it mean for a Versa resource data type to be the actual
> > resource itself, and not just its name?  It hurts my head to try to make
> > sense of that.  I think these are just names, and therefore I draw the
> > opposite conclusion.
> 
> I think of it as a name of an actual resource that resides in the
> underlying RDF graph.  The  last part - for me - is the more important
> distinction.  I guess my question is what is an example use case of a
> URI reference to a resource that does not exist in the RDF graph?

As simple as

all() -> dc:creator -> eq(<mailto:foo at yahoo.com>)

It's possible when the query is formulated that <mailto:foo at yahoo.com>
is not in the graph.  According to this magic implication we're talking
about, this should instantly become the empty set.  Or are we saying
that we would *mandate* lazy determination of the value of that item?

I think this is crazy enough, but it becomes even crazier when you try
to apply basic logic to it:

all() -> dc:creator -> neq(<mailto:foo at yahoo.com>)

Would now include resources that do not have dc:creator, as I understand
your Mike's proposition, because it now meets the test
(<mailto:foo at yahoo.com> *is* the empty set).

And what of the simple query 

<mailto:foo at yahoo.com> = <mailto:bar at yahoo.com>

If neither resource is in the context model, should this query not
result in True?

I guess I cannot even begin to make this idea make sense to me.


-- 
Uche Ogbuji                               Fourthought, Inc.
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