- From: <gstoil@image.ece.ntua.gr>
- Date: Wed, 21 May 2008 08:20:38 -0000
- To: schneid@fzi.de, hoekstra@uva.nl
- Cc: public-owl-wg@w3.org
Hi, I am afraid that this attempt is deemed to be incomplete. Then why not also mention the equivalence between maxQualifiedCardinality(0 R (complementOf C)) and allValuesFrom( R C )? And then why not transitiveRole(R) and subPropertyOf(subPropertyChain (R R) R)? And why not ... -gstoil > -----Original Message----- > From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] > On Behalf Of Rinke Hoekstra > Sent: Wednesday, May 21, 2008 10:12 AM > To: Michael Schneider > Cc: OWL Working Group WG > Subject: Re: ISSUE-125 (min1some): Min 1 QCR = someValuesFrom - Serialize > as someValuesFrom? > > > Hi, > > I suppose, the least we could do is add a short description of some of > these equivalencies to the Primer. For instance at [1] to mention the > equivalence between minCardinality and someValuesFrom. And at [2] to > say something about equivalentTo vs. subClassOf. Conversely, some > notions seem intuitively equivalent, but are not, such as functional > properties and exactly 1 cardinality restrictions. > > -Rinke > > [1] > http://www.w3.org/2007/OWL/wiki/Primer#Adescriptionobjectpropertymincardin > ality > [2] http://www.w3.org/2007/OWL/wiki/Primer#Aclassequivalentto2way > > On 20 mei 2008, at 22:00, Michael Schneider wrote: > > > I strongly concur with Bijan's points, and want to add a few more. > > > > First, I have to apologize to discuss this topic while the issue is > > still in > > "raised" state. But I cannot attend tomorrow's telco (travelling to > > Romania), > > so I am going to say, what I would say there, here. > > > > It is intended that OWL provides different ways to express > > semantically > > equivalent things, because OWL is not only a reasoning formalism, > > but also a > > modeling language. That's why we now have owl:disjointUnion, which > > gives > > additional modeling power to OWL 2 in exchange for forward- > > compatibility, and > > without enhancing the semantic expressivity of the language. > > > > OWL 1, btw., also contains a lot of syntactic sugar: > > owl:equivalentClass can > > be substituted by two rdfs:subClassOf axioms, which would bring > > certain OWL 1 > > ontologies nearer to RDFS. Or there is owl:AllDifferent, or HasValue > > restrictions. Even owl:sameAs can be expressed by means of a nominal- > > based > > class assertions. > > > > For the case of >=1-QCRs vs. SomeValues-restrictions: These are pretty > > different modeling tools, which just happen to be equivalent > > technically. For > > example, it might make sense, from a modeling perspective, to > > explicitly > > express [1..*] relationships between two classes, or even [0..*] > > relationships, although the latter would be redundant technically. > > Making > > these features illegal in OWL, and demanding to circumscribe them in a > > technically equivalent way, would not be what I want in such a case. > > Actually, > > this would be the situation of pre-OWL-2, where it was well known > > how to > > circumscribe QCRs. But people asked for QCRs often enough, anyway, > > probably > > not without a reason. > > > > Even worse than disallowing >={0|1)-QCRs would it be to demand from > > the OWL > > tools do the transformation themselves. I just try to compare this > > with the > > strange situation where my Java programming IDE would rewrite all my > > generics, > > autoboxing, non-indexed loops, and all the other stuff which does > > not go into > > the bytecode eventually, just in order to make it more Java-1.0 > > compatible. I > > would certainly not use this IDE ever again. :) And then I try to > > imagine > > Topbraid Composer, which would have to serialize my >=1-QCR silently > > into a > > SomeValues-restriction. I expect this would probably lead to a lot > > of traffic > > in Holger's mailing list... :-/ > > > > Cheers, > > Michael > > > >> -----Original Message----- > >> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org > >> ] > >> On Behalf Of Bijan Parsia > >> Sent: Monday, May 19, 2008 10:37 PM > >> To: OWL Working Group WG > >> Subject: Re: ISSUE-125 (min1some): Min 1 QCR = someValuesFrom - > >> Serialize as someValuesFrom? > >> > >> > >> So: > >> 1) intention hiding and non-roundtrippable; plus it frustrates the > >> hell out of users when you silently change what they wrote > >> 2) non-orthogonal; we need the general form in order to handle > >> larger cardinalities anyway, so would have to impose a rather strange > >> restriction > >> 3) unnecessary; if users want to write their ontologies this way > >> (so > >> as to be compatible) then can easily do so, or postprocess. > >> Furthermore, you could have a preprocessor before your old tool that > >> did this, no need to build in this kind of strangeness into the base > >> language. > >> > >> I propose closing this, with no change, on these grounds. I don't > >> think we need to note the equivalence in the spec either (there are > >> lots of equivalences...I don't see why this one is particularly > >> interesting). > >> > >> Cheers, > >> Bijan. > > > > ----------------------------------------------- > Drs. Rinke Hoekstra > > Email: hoekstra@uva.nl Skype: rinkehoekstra > Phone: +31-20-5253499 Fax: +31-20-5253495 > Web: http://www.leibnizcenter.org/users/rinke > > Leibniz Center for Law, Faculty of Law > University of Amsterdam, PO Box 1030 > 1000 BA Amsterdam, The Netherlands > ----------------------------------------------- > >
Received on Wednesday, 21 May 2008 08:21:32 UTC