- From: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
- Date: Thu, 08 Mar 2012 17:22:24 +0000
- To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- CC: public-prov-wg@w3.org
On 08/03/2012 15:44, Luc Moreau wrote: >>> The first two look reasonable to me, but I still don't see why >>> wasDerivedFrom(e2,e1,a,g2,u1) is needed. Once we have expressions >>> that explicitly name activities, how much real value is there in >>> having the "short cut" form? Can't this be expressed by having an >>> explicit activity record, etc.? >>> >>> (I'm not suggesting the model should not be capable of expressing >>> this information, just arguing against this overloading of the >>> wasDerivedFrom record which AIUI is primarily an entity-entity >>> relation.) >> >> It does seem like bundling everything into one >> wasDerivedFrom(ie,e2,e1,a,g2,u1,attrs) is more complicated than simply >> requiring three distinct statements >> >> wasDerivedFrom(id1,e2,e1,dattrs) >> wasGeneratedBy(id2,e2,a,t2,gattrs) >> used(id3,a,e1,t1,uattrs) > > The problem is that you could have another usage > > used(id4,a,e1,t1',u4attrs) > > at a different time t1' not causing the derivation. > > Also, a2 could also use e2 and generate e1 at the same time as a. > > wasGeneratedBy(id2,e2,a2,t2,gattrs) > used(id3,a2,e1,t1,uattrs) > > So, it's essential to list the activity/usage/generation *in* the derivation > expression. OK, *now* I understand the driving requirement. It's the particular derivation path that cannot (necessarily) be inferred from the separate statements, right? I'll mull it over. #g --
Received on Thursday, 8 March 2012 17:29:25 UTC