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Re: Axiom annotations

From: Michael Schneider <m_schnei@gmx.de>
Date: Mon, 23 Apr 2007 21:15:06 +0200
Message-ID: <462D05BA.2070807@gmx.de>
To: bparsia@cs.man.ac.uk
CC: public-owl-dev@w3.org

Hi Bijan, sorry for the late response!

Bijan Parsia wrote on Thu, 19 Apr 2007:

> On Apr 19, 2007, at 9:38 PM, Michael Schneider wrote:

>> And what exactly do you mean by "getting out of sync"? Do you mean  
>> some situation of the kind where I change e.g. the subject of the  
>> spo statement, but forget to also update the rdf:subject's value of  
>> the reified statement?
> Yes.


>> Such kinds of mistakes can easily happen when doing /manual/ editing.
> I thought that was a precondition of this discussion given all your  
> talk about looking at the RDF.
>> But, personally, I nearly never edit ontologies without a proper  
>> tool (exceptions are sometimes trivial ontologies for demonstration  
>> purposes in mailing list postings).
> Then I don't understand why we are even having this conversation :)
>> For example, I have just created an ontology with the Topbraid  
>> Composer (TBC) ontology editor, containing a single statement 'i1 p  
>> i2', and then I reified this statement (reification of statements  
>> is directly supported by TBC in a pretty convenient way). Then, I  
>> changed the name of individual 'i2' to 'i3'. This changed both, the  
>> object name of the regular statement, and the rdf:object's value of  
>> the reified statement. So no danger of getting out of sync here!
> But then what do you care about the "big honking chunk of  
> reification" in your ontology? The tool will take care of it.

Well, I said that I prefer using a tool for /editing/ ontologies. I
experience it to be error prone and a lot of work to even create/modify
small OWL ontologies by hand. On the other hand, I do /not/ always
/watch/ OWL ontologies through an OWL browser. IMHO, OWL/RDF is quite
readable, and at least for small to medium OWL ontologies like e.g.
wine.owl or pizza.owl, I was always able to get a good overview of those
ontologies within reasonable time by just looking at the RDF/XML syntax.

I think that good readability of at least the primary serialization
format of OWL is an aspect, which might be of some importance, if OWL is
going to become a widely spread language for the semantic web.

>> I still prefer the approach of having /always/ spo, and only  
>> additional reification, if needed!
> Why?

Replacing an spo form axiom by an analog reification quad will most
probably make it much harder for me to quickly look through an ontology
and see what's in. I imagine the case of swoogling and looking through
the result set. Hopefully, I will then have a nice web browser extension
for conveniently watching OWL files - but currently I don't have any.

With my approach (additional reification, no replacement), it will
probably be somewhat easier. Though the same reification quads are in
the file as in the currently drafted approach, I will then know that I
can just ignore all this reification stuff, if all I am interested in is
the axioms within the ontology. On the other hand, if I really am
interested in annotations, then I know where to search: Look for
reification stuff!

I admit that my approach isn't really a big matter - neither
conceptually nor technically. But it would at least provide a better
distinction between the "real" content of an ontology, i.e. the axioms,
and the annotations.

BTW, This separation could be effectively supported by pretty simple
tool support: Just a little syntax highlighting or section folding is
sufficient to also /visually/ separate the axioms from the annotations.

One last word about the ID trick that we were talking about earlier:
This won't of course work anymore, if the RDF reification vocabulary is
/not/ being used. But what remains is the separation between axioms and
annotations in the RDF mapping, as mentioned above.

> I'm loathe to use reification in general, but if we do, then given  
> this bit i see no reason for including both. I'm convinced enough to  
> suggest that you file a bug report in the owl 1.1 issues list.

I will consider to file two proposals: One for using an alternative
reification vocabulary (not RDF reification). And another one for my
"always spo" approach. But I will wait with this until this thread has
effectively ended.

Received on Monday, 23 April 2007 19:15:23 GMT

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