Re: PROV-ISSUE-452: what is plan in association inference [prov-dm-constraints]

Hi Luc,


I don't see a need to raise issues about things that can be fixed easily through discussion.  It just clogs the issue system.

If we are treating "-" as an explicit "no plan" argument in association statements, then the most general form is "there exists _pl such that ... (... _pl ...).  So the urrent form of the rule already subsumes the disjunctive form you suggest.  (Having rules with explicit disjunctions in the heads is a bad idea, as it will take us outside a well-behaved rule formalism.)

--James

On Jul 18, 2012, at 10:20 AM, Tom De Nies wrote:

> Isn't this related to the notion of default values for optional attributes?
> http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#optional-attributes
> 
> I think you're correct that we need to clarify this somewhere earlier in the document.
> Perhaps we can expand the conventions section (1.1) with the used notational conventions, such as the underscore for arguments that only occur once in a constraint/inference. Maybe we could use a similar symbol for possibly empty attributes, or just specify here that although the constraints always specify all arguments, those with an underscore that are optional, can possibly be omitted when applying the rule, 
> 
> Tom
> 
> 2012/7/18 Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
> PROV-ISSUE-452: what is plan in association inference [prov-dm-constraints]
> 
> http://www.w3.org/2011/prov/track/issues/452
> 
> Raised by: Luc Moreau
> On product: prov-dm-constraints
> 
> 
> Some inferences allow new association statements to be inferred.
> See:
> 
> http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#inference-attribution
> http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#inference-delegation
> 
> When we write: wasAssociatedWith(_id2;a, ag2, _pl2, _attrs2) in the consequent,
> a plan may not necessarily exist.
> 
> So, shouldn't it be:
> 
> wasAssociatedWith(_id2;a, ag2, _pl2, _attrs2)
> or
> wasAssociatedWith(_id2;a, ag2, -, _attrs2)
> 
> 
> 
>