[seek-kr-sms] property restrictions in growl

Serguei Krivov Serguei.Krivov at uvm.edu
Mon Aug 2 07:47:46 PDT 2004


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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