- From: James Cheney <jcheney@inf.ed.ac.uk>
- Date: Thu, 9 Aug 2012 15:06:21 +0100
- To: James Cheney <jcheney@inf.ed.ac.uk>
- Cc: Jun Zhao <jun.zhao@zoo.ox.ac.uk>, Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>, public-prov-wg@w3.org
Oops, I forgot to add a link to the new section: http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#validation-process-overview-1 --James On Aug 9, 2012, at 3:03 PM, James Cheney wrote: > Hi, > > To (begin to ) address the issue and hopefully also satisfy requests from reviewers for better intuition about how normalization/validity checking/equivalence checking work, I have added an outline of the validation process (complementing Tim's contributed figure). > > This is work in progress, but I hope it can give people confidence that this issue is addressed (and can be explained so that it is clear to other readers that it is addressed). > > I have marked this pending review, hopefully we can close it or identify further action to take to resolve it during the meeting. > > --James > > On Aug 9, 2012, at 11:25 AM, Jun Zhao wrote: > >> 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 >> >> > > > -- > The University of Edinburgh is a charitable body, registered in > Scotland, with registration number SC005336. > > > -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
Received on Thursday, 9 August 2012 14:07:09 UTC