- From: Ivan Herman <ivan@w3.org>
- Date: Wed, 11 Aug 2004 09:17:51 +0200
- To: Natasha Noy <noy@SMI.Stanford.EDU>
- Cc: public-swbp-wg@w3.org
- Message-ID: <4119C81F.1040203@w3.org>
Natasha Noy wrote: >> A small remark: for the diagnosis relation example I would expect to >> have a cardinality restriction on the diagnosis_value and the >> diagnosis_probability set to one (there must be a diagnosis, after >> all...). I do not think that the the fact of defining this as a >> functional property covers that (functional means that there must be >> at most one value, right?) You use the cardinality restriction in the >> 'buyer' relation later. Regardless on how one interprets this very >> example, I think the usage of cardinality is very important in n-ary >> relations in general, so it might be more 'didactic' to use it imho. > > > Yes, you are right. We tried to be reasonably careful about this, but > apparently not completely. Indeed, making something a functional > property sets the max cardinality to 1, but doesn't require a value. > Setting cardinality for diagnosis_value to 1 would make a lot of sense. > I am not sure though if diagnosis_probability should require a value. > What if we don't know the probability? > Fair enough (although, personally I would be scared if my doctor could not tell me anything on that;-) >> Also, in this example, I would expect the diagnosis probability >> relation to be a datatype property rather than an object property, >> with an xml schema datatype of an interval between 0 and 1. After all, >> this is what probability is... (at least as an alternative example to >> the 'literal' type object property you seem to use right now) > > > I think in this example probability really is a qualitative measure, > rather than a quantitative one. I think we talk about someone with high > probability of breast cancer, rather than about someone with probability > of breast cancer at 0.85 Besides, OWL doesn't have a good way of > defining property ranges, and we'll leave that to a different TF note to > discuss. It's probably not very relevant for this particular note (We > struggled quite a bit to isolate all the related thorny issues) > I agree for this particular note. But it would be nice if the SWBPD would come out with a note where datatype properties are used, possibly with some restrictions. The specs are pretty scarce on that subject... >> A slightly different question: I am not sure what a DL reasoner would >> do if, say, Diagnosis_relation was also defined to be of a type >> rdfs:Statement. It may not add anything to any inference results, but >> might have a 'descriptive' value nevertheless. But I am a bit out of >> my league to predict the behaviour of a DL reasoner on this... > > > It's out of my area of expertise as well, but I don't think making it > rdf:statement would change much. > > Natasha > > -- Ivan Herman W3C Head of Offices C/o W3C Benelux Office at CWI, Kruislaan 413 1098SJ Amsterdam, The Netherlands tel: +31-20-5924163; mobile: +31-641044153; URL: http://www.w3.org/People/all?pictures=yes#ivan
Received on Wednesday, 11 August 2004 07:18:06 UTC