SUO: Re: W3C approves RDF and OWL as recommendations
Danny, Adam,
I did NOT suggest that categories like the relation type parent (with
a lowercase 'p') and the concept type Parent (with an uppercase 'P')
could be "combined" and I explicitely said that they were exclusive:
> these two categories are exclusive (e.g. in the SUMO, parent
> would be abstract while Parent would be physical)
Danny wrote:
> What's to stop you saying the same thing in RDF?
> parent rdf:type rdf:Property .
> parent rdfs:subClass Animal .
In RDF/OWL, classes are exclusive with properties, thus what you
suggest is inconsistent with the definitions. The fact that your
Notation 3 parser did not detect this inconsistency means that it
is not RDF/OWL compliant.
More intuitively, I do not see how something could be both
categorized as abstract and physical. That does not mean that I
reject new categorization schemes, but this is not what I introduced.
Thus, I did NOT suggest that the relation type parent
(with a lowercase 'p') could be a subtype of Animal.
What I have suggested is a shortcut to avoid the users having to
(i) declare both the relation type and the concept type (i.e.
duplicate role types from the concept type hierarchy into the
relation type hierarchy),
(ii) write definitions to connect them.
This was a way to answer the knowledge sharing/retrieval problems
pointed out by Asha while still using the "set-theoretic approach"
(Asha's expression) and the usual ontological distinctions.
Thus, for KIF, I suggested that a relation type roleTypeDomain
could be defined in such a way that the following 3 formulas
(subclass Parent Animal)
(roleTypeDomain Parent 1 Animal) (roleTypeDomain Parent 2 Animal)
are equivalent to the following 6 formulas:
(subclass Parent Animal) (instance parent binaryRelation)
(domain parent 1 Animal) (domain parent 2 Animal)
(=> (parent ?A1 ?A2) (Parent ?A2))
(=> (Parent ?A2) (exists ((?A1 Animal)) (parent ?A1 ?A2)))
Danny wrote:
> "an increase of the complexity..." - an increase from which baseline?
1) For the users, "complexity" just meant "complication": double
declarations + definitions
2) For the inference engines, I was thinking about the additional work
that the handling of double declarations plus the definitions would
implies (if the users do not forget to enter them and if the language
supports the entering of such definitions; do you think OWL can?);
conversely, if the semantics of primitives such as roleTypeDomain is
hard-coded in the inference engine, they can be handled more
efficiently than their underlying rules.
Danny wrote:
> I'd also note that there's the assumption here that both Parent and
> parentOf would both be needed. If only the class (or relation)
> were needed, then surely there is a net *reduction* in complexity
> from the combined notion.
Ok, you acknowledged that I was not suggesting a "combined notion"
and you introduced that idea. I will not comment on that idea on
ontological grounds since this is not my goal: my goal is to store
distinctions into a same ontology and interlink them in a correct
way in order to help their automatic or manual comparison and hence
their retrieval or understanding, and the checking of their uses.
Philippe