- From: Jun Zhao <jun.zhao@zoo.ox.ac.uk>
- Date: Thu, 09 Aug 2012 11:25:08 +0100
- To: public-prov-wg@w3.org
James and Stian, On 08/08/2012 11:33, James Cheney wrote: > OK, I will revise to make this clearer. This can be done by adding explanation rather than by making technical changes, though, so we should focus on resolving the other issues now. > +1 -- Jun > --James > > On Aug 8, 2012, at 11:02 AM, Stian Soiland-Reyes wrote: > >> On Wed, Aug 8, 2012 at 10:47 AM, James Cheney <jcheney@inf.ed.ac.uk> wrote: >>> I understand your concern. At a purely technical level, we avoid nontermination, but only by drawing a fine distinction between having an entity(e) statement in the instance, and "knowing e is an entity" (represented by entity' \in typeOf(e)). >>> >>> We (me, Luc, Paolo, Tom) discussed three ways of avoiding this problem, before finalizing the review copy: >>> >>> 1. Drop the entity-generation-invalidation and activity-start-end inferences altogether. >>> 2. Add some limitation to inference (such as your suggestion of not triggering inferences on generated existential variables, or applying the ) that recovers finiteness. >>> 3. [what we have done] demote the type inferences to only infer constraints like 'entity' in typeof(id) , not add new statements like entity(e) to the PROV instance. >>> >>> Of the three, the one with strongest consensus was (3). Some of us strongly felt that the e-g-i and a-s-e inferences are needed. Others, including me, strongly felt that (2) would be a bad idea, as it breaks the connection to logic (i.e., the e-g-i and a-s-e and may have more radical unforeseen consequences. >> >> OK, I see now that you have thought about this. It would be useful if >> some of those considerations shone through to the document. I can >> agree on argument 3 if we formulate it well, explicitly. >> >> I agree that the inferences are needed, or at least useful. >> >>> We believed that (3) was an acceptable compromise (if a bit hacky), but, I'm not sure how the group as a whole would feel. That is why I'm laying out the options we considered. >>> So, my proposal would be to make this distinction clearer (and explain why) so that it does not surprise or bite people... >> >> I would think this is the best approach, rather than dropping the >> inferences all together, as the rest of the constraints rely on them. >> >> -- >> Stian Soiland-Reyes, myGrid team >> School of Computer Science >> The University of Manchester >> >> > > -- Jun Zhao, PhD EPSRC Postdoctoral Fellow Department of Zoology University of Oxford Tinbergen Building, South Parks Road Oxford, OX1 3PS, UK
Received on Thursday, 9 August 2012 10:25:32 UTC