Re: Comments on Section 3

Kevin Smathers wrote:
> 
> On Mon, Apr 14, 2003 at 06:17:09PM -0400, David R. Karger wrote:
> 
> > I feel the same way about statements (I'm not going to try to define
> > facts).  An "a R b" statement is unique.  If two people make the same
> > "a R b" statement then that is exactly what happened: they asserted
> > the SAME statement.
> 
> Just because the content of the statement is identical doesn't mean that
> you can validly collapse all of the statements with that content to a
> single instance.  The content will remain identical even if there are
> multiple instances, but the address distinction between the statements
> will be lost if the instances are collapsed.  Neccessarily therefor,
> collapsed statements represent a loss of information.

Some terminology that might help with this discussion is that of "statements"
and "statings" (see the RDF Core WG discussions on reification). A "statement"
is the abstract thing, of which there is only one for each "a R b". A "stating"
is the occurrence of some statement in a context (e.g. in some XML file or
database).

The WG decided that an RDF reification represents a stating rather than a
statement, so there can be more than one for each "a R b" triple.

Statements don't have "addresses" so there is no address distinction to
maintain. Reified statements do have addresses, URI's or bNodes. 

Thus I would suggest that both people are asserting the truth of the same
"statement" but are doing so via different "statings". If you wish to represent
the stating explicitly within the RDF data model then use reification. As
defined in the RDF Model theory you can't collapse multiple reifications
(statings), they are different resources, but you *can* collapse multiple
statements.

> Your argument that the users intent all along should have been to
> assert the same instance as had been asserted previously is presuming
> to know the intent of the user.   If the user had that intent, then
> there is no reason for them not to use the preexisting statement
> directly.

Not sure that is ever a good idea. If Jim asserts "a R b" using a stating with
URI "S1", then Jill asserts "a R b" I'd prefer to note that as another stating
with a different URI (address) "S2" - after all they have different provenance.
I'd rather Jill did not try to pretend that she made stating "S1" even though
she did assert the truth of the same abstract statement "a R b".

Dave

Received on Tuesday, 15 April 2003 11:30:20 UTC