[Fwd: Re: SUO: Re: W3C approves RDF and OWL as recommendations]
Sorry, the following was not reflected yesterday because of a recent address
change on my side:
-------- Original Message --------
Philippe Martin wrote:
I wonder whether you aware that OWL DL as a DL should support to a cetain
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)))
"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.
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.
this connection between relational concepts and their respective relations,
e.g. by its "some" operator (in KRSS-syntax),
in OWL DL expressed more verbose by "... restriction ... someValuesFrom
Therefore Parent := (some isParentOf)
should suffice for a DL inference engine
together with the first domain axiom of isParentOf to classify Parent
as a subconcept of Animal,
furthermore, to enumerate by the way of "instance classification"
the instances of Parent from known isParentOf-assertions in addition to
instance assignments to Parent.
On the other hand, explicit knowledge of the rules per se
(=> (isParentOf ?A1 ?A2) (isInstanceOf ?A1 Parent))
(=> (isInstanceOf ?A1 Parent)(exists ?A2 (and (isInstanceOf ?A2 Animal)(isParentOf ?A1 ?A2))))
is beyond the answer facilities of a standard DL system.
If you want to know, whether OpenCyc 0.7 is able to represent and answer
see my inquiry at