There is still an active debate on whether a Taxon (TaxonConcept) is a individual or a class (at least in my mind). From the OWL perspective it can't be both or it pushes us into OWL Full and possible undecideability.

Should we not do anything until we can settle this discussion  (it is at the heart of modelling our domain)  or should be simply agree that it may be modelled as either class or instance but that we still be defined it as existing?

I prefer the latter course. The 'correct' or optimal answer to the question depends on what the model if for and as that is incredibly vaguely specified it provides us with no  grounds for testing proposed solutions. We could discuss till the cows come home and no one would ever be right or wrong and we would never have a way of ascertaining when we got to the end of the discuss. Life, after all, is short.

On the specific example that Bob mentions I wonder why we need the property at all. The notion of ownership is not restricted to biodiversity informatics. 

dc:rightsHolder
http://purl.org/dc/terms/rightsHolder
"A person or organization owning or managing rights over the resource."

Would probably do the job and be understood by every application that 'understood' DC. Likewise a specimen is dc:isPartOf a collection (A related resource in which the described resource is physically or logically included.)

I am not aware of a way of suppressing assertions imported as part of an ontology. If I import TaxonConcepts that some one has helpfully tagged with dc:title assertions then they will be treated as instances by OWL not classes (classes aren't the subject or object of propeties only individuals are) unless I declare dc:title an OWL annotation property which will of course remove dc:title from all inference where it may be used elsewhere on real instances of things in my combined ontology. The only thing to do is to manually (or programmatically) remove all the offending triples on import. I'd like to know a better way of doing this.

But I should shut up as I am supposed to be on holiday.

All the best,

Roger





 

On 18 Oct 2009, at 15:38, Jonathan Rees wrote:

On Sun, Oct 18, 2009 at 10:02 AM, Roger Hyam <rogerhyam@mac.com> wrote:
Hi Bob,

This is why I believe we should not make assertions in the core
ontology about range and domain of properties.

If some one wants to import these notions (terms) then they are forced
to also import our (possibly flawed) world view.

If we were to create a perfect model of the reality of the
biodiversity informatics domain in OWL (or XML Schema or UML or
alphabetti spaghetti) due to Hyam's unoriginal law* it would be wrong
next week or certainly by the next TDWG meeting.

There is a different view, adopted by many ontology projects: You do
the best you can, and then if you find a mistake in the ontology, you
fix it.

Without guidance such as domain and range, you increase the
probability that curation will be inconsistent across projects. And
inconsistency makes data integration harder down the road, pushing
work that ought to be done once, at curation time, off onto hapless
consumers, each of whom has to do cleaning and normalization
separately.

The ontology is a significant point of leverage and it would be a
shame not to use it.

The OWL reasoners are really helpful at findings bugs like this one.
Public review helps too, as we have just seen.

If someone wants to ignore domain, range, subclass, etc. because
they're afraid they contain mistakes, that's pretty easy to do. If
someone wants to know how to use the ontology consistently with how
others are using it, that's hard to do, if the information they need
isn't in the ontology.

Jonathan Rees
Science Commons

This is why we should perhaps  have a list of terms (bound to URIs)
and a separate set of models that are used for particular occasions.
Ultimately the semantics of the data is governed by the query that is
being asked i.e. it is context sensitive. "Give that XYZ, what are the
ABC?"

* Hyam's unoriginal law states "The future is different - that is how
we tell it isn't the present."

Hope this helps,

Roger



On 17 Oct 2009, at 22:45, Bob Morris wrote:

http://rs.tdwg.org/ontology/voc/Collection.rdf#hasOwner
specifies two classes in its range: Person and Institution,

The formal semantics of rdfs:range entails that the actual range of
an object property is the intersection of the named rdfs:range
classes.

I believe this all entails that the only owner of a Collection is
something that is both a Person and an Institution.

Also, since these classes are not(?) defined as disjoint, the result
is that any set of triples
  Roger rdfs:type Person
  C hasOwner Roger
turns Roger into an Institution

Likewise
  Kew rdfs:type Institution
  C hasOwner Kew
turns Kew into a Person


I could be wrong about all this, perhaps unless I too am an
Institution, since, in my experience, Institutions rarely admit to
being wrong. (Uh, oh, better not go there... :-)  )


Bob Morris


p.s.
This also suggests that the stylesheet human.xsl is somewhat
recalcitrant, since the html rendering of
http://rs.tdwg.org/ontology/voc/Collection.rdf only sees Institution
as the range of hasOwner






--
Robert A. Morris
Professor of Computer Science (nominally retired)
UMASS-Boston
100 Morrissey Blvd
Boston, MA 02125-3390
Associate, Harvard University Herberia
email: ram@cs.umb.edu
web: http://bdei.cs.umb.edu/
web: http://etaxonomy.org/FilteredPush
http://www.cs.umb.edu/~ram
phone (+1)617 287 6466
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