Re: PROV-ISSUE-645 (TomDN): Should we add a new constraint on EmptyCollection and Dictionary? [PROV-DICTIONARY]

As mentioned in the issue, Sam and I are not in favor of adding a new
constraint for this.

Proposal to resolve this issue: Keep EmptyCollection and Dictionary
unconstrained (Do not add a new constraint on EmptyCollection and
Dictionary), because it would facilitate a way of specifying
EmptyDictionary we should not encourage:
i.e.
entity(d, [prov:type="prov:Dictionary", prov:type="prov:EmptyCollection"])
instead of
entity(d, [prov:type="prov:EmptyDictionary")

If any members of the WG have an objection to this, we ask kindly to
inform us by replying to this email. If no objections are received before
Tuesday March 26th, we will assume this resolution is accepted,

- Tom


2013/3/7 Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>

> PROV-ISSUE-645 (TomDN): Should we add a new constraint on EmptyCollection
> and Dictionary? [PROV-DICTIONARY]
>
> http://www.w3.org/2011/prov/track/issues/645
>
> Raised by: Tom De Nies
> On product: PROV-DICTIONARY
>
> Originally raised by Khalid, and agreed to discuss before the next release.
>
> Khalid's email:
> >Regarding prov:EmptyDictionary, I think there is anew constraint
> >that can be added to state that an entity that is both a dictionary
> >and an empty collection is an empty dictionary.
>
> My response:
> I would be cautious to adding new constraints, especially with PROV-DM
> constructs on the left-hand side.
> Note that we have the reverse, in constraint D12.2. Technically, your
> constraint is correct and doesn't break anything. I guess I just don't see
> a use case where one would want to write:
> entity(d, [prov:type="prov:Dictionary", prov:type="prov:EmptyCollection"])
> instead of
> entity(d, [prov:type="prov:EmptyDictionary")
> This is, in my view, a way of specifying EmptyDictionary we should not
> encourage.
>
>
> I would like to ask the opinion of the group on this before we the final
> release.
>
>
>
>