RE: OWL2 monotonicity (was How do you deprecate URIs? )

Hi again Bijan,

> From: semantic-web-request@w3.org
> [mailto:semantic-web-request@w3.org] On Behalf Of Bijan Parsia
> Sent: Tuesday, July 15, 2008 1:42 PM
> To: semantic-web at W3C
> Subject: Re: How do you deprecate URIs? Re: OWL-DL and linked data
>
>
> On 15 Jul 2008, at 18:15, Booth, David (HP Software - Boston) wrote:
>
> >> From: Michael Schneider
> >> [ . . . ]
> >> OWL 2 DL won't define any (reasoning) semantics for
> >> annotation properties.  So owl:sameAs will *not* transfer the
> >> deprecation triple to the other URI.
> >> (Again, this is the current state, which might change
> >> before OWL 2 DL becomes a W3C recommendation.)
> >
> > This *must* changed to make OWL 2 DL a monotonic extension of RDF:
> > http://www.w3.org/TR/rdf-mt/#MonSemExt
>
> First, I don't think there is a monotonicity requirement. Certainly
> not expressed from that section.
>
> Second, I don't see that this is nonmonotonic. OWL DL isn't an
> extension of RDF or RDFS. This is well known. (It's an extension of a
> subset of them.)

To clarify my concerns:

 - I think it is architecturally critical that for any RDF graph that may include non-OWL2 monotonic semantic extensions, if the graph has entailments E without applying the OWL 2 semantics, then all of those entailments E should still be valid when OWL 2 semantics are applied, i.e., the OWL 2 entailments monotonically extend the existing entailments.  (And yes, I mean "monotonic" in the usual sense.)

 - As described by Michael, OWL 2's annotation properties sound like they would violate this, as you indicated they would for OWL 2 Full:

> [ . . . ]
> >> In OWL 2 Full, being an RDF compatible language, it is not
> >> possible to
> >> define such a kind of "semantic-freeness". Here, owl:sameAs
> >> *will* transfer the deprecation triple to the other URI.

I don't mean to irk anyone, but I do mean to be clear that I think semantic monotonicity is architecturally *critical*, so that RDF tools and reasoning can be safely applied to *all* RDF graphs, regardless of whether or not a graph uses OWL 2.  This is particularly important when RDF graphs are combined from many sources, some of which may use OWL 2 and others not.

I hope this clarifies my concerns and the reasons for them.



David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

Statements made herein represent the views of the author and do not necessarily represent the official views of HP unless explicitly so stated.

Received on Wednesday, 16 July 2008 17:51:26 UTC