- From: Daniel Elenius <daele@ida.liu.se>
- Date: Sun, 21 Nov 2004 12:19:42 -0800
- To: Ian Dickinson <ian.dickinson@hp.com>, public-sws-ig@w3.org
Ian Dickinson wrote: > > Daniel Elenius wrote: > >>> * also in section 5.4, there seems to be no syntactic difference >>> between ControlConstructBag and ControlConstructList, so why not >>> just make one a sub-class of the other? >> >> But there is a *semantic* difference, i.e. the bag should not be >> interpreted as ordered. > > Yes, I understand that such is the intent. I was just pointing out > that there's no semantic or syntactic difference at the RDF level. In > OWL terms, the ccBag and ccList classes are co-extensional. Any > semantic difference derives from an owl-s -aware processor being > programmed to recognise those names and treat them specially. > Of course, but that happens all over the place in OWL-S. An OWL-S document is not much use without an OWL-S-aware processor. Looking only at the RDF level, there is also no difference between Split, Split+Join, Choice, and Any-Order, except their URIs. So, using the same reasoning, would you want to turn them all into one class? >> Then again, it doesn't really hurt to have the two classes, I think. > > Perhaps it simply suggests that some refactoring might be indicated. > There are two needs: to encode sematically meaningful distinctions > (like duplication or ordering) that *are* relevant to the > interpretation of the language, and to encode data-structures using > the low-level machinery of RDF. It may be that these are not as > cleanly separated as would be nice in a specification document. > So, how would you do it? I'm sure everybode would be happy to encode both lists and bags in a more convenient format, but it's hard to see how to do that in OWL DL. > Ian > Cheers, Daniel
Received on Saturday, 20 November 2004 20:19:38 UTC