- From: Evan Wallace <ewallace@cme.nist.gov>
- Date: Thu, 24 Oct 2002 12:03:41 -0400 (EDT)
- To: www-webont-wg@w3.org
Peter Patel-Scheider wrote: >To further this, > _:x owl:disjointUnionOf [_:d1 ... _:dn] . >has the same meaning (ignoring the RDF triples that arise from the syntax) as > _:x owl:unionOf [_:d1 ... _:dn] . > _:di owl:disjointWith _:dj . 1<=i<j<=n > >The only thing going for owl:disjointUnionOf is that it uses fewer triples >than the alternative. However almost all disjoint unions are small so the >number of owl:disjointWith triples will not be that large. This is pretty much what I asked for in Bristol. Because of this, (and because I couldn't find anyone at NIST who objected to it) I expect to concur with the recommended issue resolution. However, I don't believe that statements such as the last sentence above are very meaningful. How do we know the set of "all disjoint unions"? What is "small" in this context? What does "almost all" mean? In an EXPRESS model for cutting tools [1] which is a precursor to an ISO standard for same, I found 34 occurances of the the equivalent EXPRESS syntax for disjointUnionOf, ONEOF. The average size of the class lists which were the object of these statements was 4. I would agree that is small. However, the largest size was 11. That expands to quite a few more disjointWith statements than I would want to write by hand. Which leads to the following. What is clear to me is that some n-ary form of Disjoint will exist in the presentation syntax of tools that create OWL Ontologies. Even in Dan's proposed example of this for our GUIDE document he left the expansion of his small list to the "editor/reader". It would make sense to include such a construct in our presentation syntaxes. It is already the natural interpretation of the predefined Disjoint constraint in UML which applies across a set of generalization relations (subtypeOf). [1] http://www.mel.nist.gov/rrm/fy97/jul97mrmodel.exp -Evan Evan K. Wallace Manufacturing Systems Integration Division NIST ewallace@nist.gov
Received on Thursday, 24 October 2002 12:03:51 UTC