W3C home > Mailing lists > Public > public-owl-wg@w3.org > January 2009

Re: LC Comment: "Hidden" Axioms

From: Bijan Parsia <bparsia@cs.manchester.ac.uk>
Date: Fri, 23 Jan 2009 22:58:27 +0000
Cc: "W3C OWL Working Group" <public-owl-wg@w3.org>
Message-Id: <E3632200-2E58-4852-A41F-F55B53E3B2EF@cs.manchester.ac.uk>
To: "Solbrig, Harold R." <Solbrig.Harold@mayo.edu>

On 23 Jan 2009, at 22:46, Solbrig, Harold R. wrote:

> The mention of "superseding" and "superseded" begins to sound like
> incremental versions.  Might one want more than just a list of what is
> "hidden" and what is "active"?  I would think that much of the value  
> of
> the non-active axioms would include, at bare minimum, the relative  
> order
> in which new axioms were introduced and "hidden" axioms were
> deactivated.

Yes, but all that can be derived from additional annotations. The only  
thing which *cannot* be gotten without a special annotation with  
hiding semantics is the hiding part.

> It would be possible to introduce new axioms via the notion of  
> additive
> "micro-versions" - incomplete collections of axioms that, when  
> combined
> with a previously complete ontology, creates a new version of the  
> same.

We had a version of this in swoop, but out of band. I.e., you could  
put a "change set" into an annotation that was associated with an  
entity and dynamically apply or revert that change set.

One might be able to hack that to work here, but it's tricky

> This still presents the same fundamental problem - how to indicate  
> that
> an axiom should no longer have logical force

Yes. Once you have that, everything else can be layered.

> - but it would allow the
> relative order of changes to be encapsulated in the information
> associated with the "micro-version" itself, something that is  
> available
> already.

I'll discuss with our folks whether a changy approach would be  

> Let me mention related requirement that we have encountered.  We  
> have a
> need to be able to classify an ontology and subsequently transmit both
> the asserted and the logical inferences for display and consumption in
> secondary resources such as wikis and other tools.  As these tools may
> create additional axioms, we need to differentiate the asserted from  
> the
> inferred - both as important information to the editors and to be able
> to remove or ignore these axioms when the modified ontology is
> subsequently re-classified. While this is a slightly different use  
> case,
> it still involves the same notion - some sort of tag or property on an
> axiom that affects the way that it is interpreted.

Actually, from a logical point of view the added inferred axioms are  
harmless...they were already "in" the annotation. So a simple  
annotation which indicates that it was inferred would be fine ---  
editors could not display them, or try to verify them, but if some  
tool passed it to a reasoner...the reasoner would just have an easier  
time :)

(Of course, if you were trying to *test* the reasoner...putting in the  
entailments from some other reasoner wouldn't be good. So there's  
still some justification there. I just think it's somewhat less severe.)

Received on Friday, 23 January 2009 22:59:04 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:42:08 UTC