RE: Properties of Properties Question

From: "Dickinson, Ian J" <Ian_Dickinson@hp.com>
Subject: RE: Properties of Properties Question
Date: Tue, 23 Oct 2001 17:50:28 +0100

> From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com]
>
> > There are a number of things that you could be asking for:
> > 
> > 1/ The ability to associate information with assertions.  (In 
> > RDF terms
> >    this would probably be using a statement as the subject of another
> >    statement, which can't be done in RDF.)  What you would be 
> > trying to do
> >    below would be to restrict the kinds of information that can be
> >    associated with a particular assertion.  This can't be 
> > done in DAML+OIL
> >    because assertions cannot have associated information.
> 
> I can see a role for things in category 1/.  A simple example, common in
> many knowledge bases, would be to say "this assertion is 50% likely to be
> true", or "this assertion holds under the following preconditions".
> Separate from the logical properties of the assertion**, it might be nice
> just to be able to record the provenance of an assertion for auditing or
> explanation purposes.  I take it from the analysis above that the only way
> to record such information in a DAML+OIL model would be to add an extra
> intervening node, from which hangs the properties of the association, so:
> 
> <x> abc:someProp <y> .
> 
> becomes:
> 
> <x> abc:someProp [<> abc:prob "0.5" ;
>                      abc:provenence <...whatever...> ;
>                      abc:hasValue <y>] .
> 
> Actually I'm not sure that the [..] context brackets are necessary, but I
> can't remember whether N3 has parentheses to sort out operator precedence.
> 
> Is there another way of handling such a requirement?

There are lots of ways to do this, even in DAML+OIL.  However, you mostly
end up having to do everything related to reasoning for yourself, as you
have placed the relevant information outside of DAML+OIL.  Whether this is
a good use of DAML+OIL is an exercise left up to the reader.  (Hint:  The
answer depends on a lot of things.)

> Cheers,
> Ian
> 
> ** i.e. to side-step the comment "RDF/DAML+OIL doesn't support approximate
> reasoning, so tough".


peter

Received on Tuesday, 23 October 2001 13:03:25 UTC