[seek-kr-sms] property restrictions in growl
Rich Williams
rwilliams at nceas.ucsb.edu
Mon Aug 2 12:28:48 PDT 2004
>
>
> Do you mean that all syntax checkers you have used would require user to
> say "property P has domain C1 and range C2) before user can say
> something like
> (forall P C3) or (>4 P C4) (????)
>
As far as I can tell, both Jena and OWLAPI require that a property be
declared before it is used. So for example
<owl:ObjectProperty rdf:ID="objProp"/>
<owl:Class rdf:ID="Test1">
<rdfs:subClassOf>
<owl:Restriction>
<owl:onProperty>
<owl:ObjectProperty rdf:about="#objProp"/>
</owl:onProperty>
<owl:minCardinality
rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
>2</owl:minCardinality>
</owl:Restriction>
</rdfs:subClassOf>
</owl:Class>
is fine in both, but remove the first line and both complain. So no need
for a domain and range specification, just a declaration of the property's
existence (which of course in OWL has an implicit range, since object and
data properties are differentiated).
Now for my 2-cents worth on this. I think that when creating a property
restriction, the user interface should have a text box that incrementally
matches on the current (object or data) property names. If the user types
in a non-existent property name, the editor should create the property, so
that it is in the list of known property names the next time a restriction
is created. The owl file needs to be saved with a property declaration in
it, otherwise no known tool will be able to read it in.
>
> I understand what are restrictions defined for a class. What do you mean
> by restriction defined at property level?
>
I think global restrictions like functional property?
>
> Thanks,
> serguei
>
> Shawn
>
>
> Serguei Krivov wrote:
> > Hi All,
> >
> > We have been working hard on first alpha release of growl. Yet we have
>
> > got a couple of important issues which probably should be resolved
> > beforehand. A long discussion between me and Rich have not brought us
> to
> > a clear consensus, so the feedback from the group is wanted at least
> for
> > the most controversial issues. Here is one:
> >
> >
> >
> > Issue #1 Should we allow user to define property restrictions without
>
> > defining explicitly the repective property? Or should we demand that
> > user alwase define a property with domain and range and only then get
> > permision to define (any) restriction on this property.
> >
> >
> >
> > We are not sure what is legal in owl, specifically in owl-dl, but we
> > have different intuitions about it. On one hand when reading a
> property
> > restriction with no explicit property definition owlapi complains
> > that it is not an owl-dl construct. Also just to exclude the
> > possibility of typos while defining restriction it would be
> advantageus
> > to have combo boxes that strictly confine the names for restriction
> to
> > link them to the properties that have been already defined.
> >
> >
> >
> > On the other hand, we know it that definition of domains and ranges is
>
> > not realy requred for tableaux algorithms to reason. Moreower -
> semantic
> > of domains and ranges in owl-dl is defined via property
> restrictions
> > which are the elementary constructs in DL. Therefore the complains in
>
> > owlapi about non-dl construct is weared. It may be related to the
> fact
> > that from owl syntax it does not follow if a restriction pertained to
>
> > data property or object property. For example here is the code:
> >
> >
> >
> > <owl:Class rdf:about="http://a.com/ontology#Object1">
> >
> > <rdfs:subClassOf>
> >
> > <owl:Restriction>
> >
> > <owl:onProperty rdf:resource="http://a.com/ontology#Relation1" />
> >
> > <owl:minCardinality
> > rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
> >
> > >2</owl:minCardinality>
> >
> > </owl:Restriction>
> >
> > </rdfs:subClassOf>
> >
> > </owl:Class>
> >
> >
> >
> > Is Relation1 an object property or a data property? From owl syntax it
>
> > does not follow and may be this is a reason for the complain. This
> > uncertainty as we see it here may be a problem of owl design , but it
> is
> > not problem of growl, since growl has different node types for object
> > property restrictions and data property restrictions. And if property
> > restrictions with no explicit property definitions are allowed in
> owl-dl
> > we have to support their editing in growl.
> >
> >
> >
> > So what we have to do with so called "non typed" property restriction
>
> > -allow them in growl or banish them from growl? Any of your thoughts
> on
> > this subject would be welcome.
> >
> >
> >
> > Thanks,
> >
> > Serguei
> >
>
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