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[protege-owl] Pellet gives strange, wrong error with Booleans
tar at ISI.EDU
Thu Aug 30 12:15:17 PDT 2007
On Aug 30, 2007, at 11:19 AM, Stephen Larson wrote:
> Sorry for not using the appropriate channels before. I have
> included other lists on this because I think that it is important
> to clear this up.
> I'm sending you the simplest example of this problem that I can
> find. It doesn't seem to happen with a single simple case of the
> presence of a boolean. The behavior appears to be more complex
> than that. But it is the case that the problem exists, I've sent
> you an example ontology that exhibits it, and it can be reversed by
> commenting out the booleans. It is reproducible if you use the
> tools that I have described.
> I understand if you are frustrated with the DIG interface. But,
> it seems like you are implying that Pellet doesn't really support
> the interface.
The issue isn't with Pellet. It was an encoding problem with
Protege's DIG interface.
I recently reported this and Tania Tudorache indicated on Aug. 28
that a fix for the problem was going in. Look for the messages on
the Protege-OWL mailing list with the subject
"Problem with DIG rendering of boolean-valued properties"
Synopsis for non-subscribers: Protege was mapping boolean datatypes
to int for DIG, but not translating the "true" and "false" values
into integers. Protege will now map true => 1 and false => 0 as
well, which should solve the problem by transforming boolean-valued
datatype properties into limited integer-valued ones.
> I'm just a naive user here with limited resources. I'd like to
> use Pellet to check out my ontology in Protege 3.3.1 without having
> to acquire a 'toolchain' in order to do it. The pellet website
> says it supports DIG: http://pellet.owldl.com/faq/protege/. But it
> seems like maybe it doesn't really. So it seems like the DIG
> interface is really just a distraction and shouldn't be included in
> code intended for naive end-users. Maybe some agreement between
> the Pellet and the Protege people to stop supporting the DIG
> interface would be the best route to avoid naive users like me from
> falling into these kinds of traps, getting misleading error
> statements and thus being unable to fix their ontologies so that
> Pellet can reason with them. I think that would be best for the
> On 8/30/07, Bijan Parsia < bparsia at cs.man.ac.uk> wrote: First,
> there is a Pellet support mailing list:
> <http://lists.owldl.com/mailman/listinfo/pellet-users/ >
> I really prefer these sorts of question to be directed there or to
> public-owl-dev at w3.org, that way more people benefit and more people
> can pitch in.
> Second, DIG is just unreliable, esp. with datatypes. I tried your
> ontology in Protege4alpha (afaict, you are using Protege 3.x, which
> really makes the report "latest Protege" meaningless). It works with
> both FaCT++ and Pellet in Protege4. It works in OWLSight.
> (You do well to try several different avenues to avoid getting stuck
> in these sorts of tool effects. These days, there are plenty of ways
> to gather data about what part of the toolchain is causing trouble.)
> So, as I cannot reproduce your problem, I don't see what it is ;) A
> tiny fragment that exactly exhibited the problem would be very
> helpful, esp. when you have the sort of evil property names such as:
> Take home lesson: DIG should be avoided, esp. with datatypes.
> Hi Bijan, Alan,
> I think I just figured out a problem that has plagued me for
> several months with individuals. When we have created individuals
> in the past, we have gotten the error message shown in the
> screenshot. However, we have never been able to find an int that
> is labelled with false. This has caused us to discard instances in
> the past in order to get rid of the problem.
> Well today, I went on the assumption that the problem is
> actually with the booleans themselves.
> <sao:sao1863785805 rdf:datatype=" http://www.w3.org/2001/
> XMLSchema#boolean "
> I've attached an ontology that has booleans in it with false as
> the value. When I run it through Pellet using the DIG interface in
> the latest Protege, it returns the error in the screen shot.
> However, when I got rid of all the statements with booleans in it,
> there is no problem, and the ontology checks out just fine.
> Is this a problem with case sensitive 'false' values or
> something? At the minimum, I feel that the error message needs to
> be corrected. Could you advise me how booleans are supposed to be
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